Japan’s population is aging at a speed unprecedented in the world, and its shortage of caregivers has become a major issue. At the same time, the Internet of Things (IoT) is expected to create unprecedented new value by connecting all people and things, allowing them to share various kinds of knowledge and information. In addition, as artificial intelligence (AI) and big data are undergoing a transformation that is changing the value of human labor, robots incorporating these innovative technologies are expected to solve the problems of the aging society. On the other hand, in the field of nursing care, the relationship between the caregiver and the care-receiver is basically a person-to-person connection. There is a question of how people and technology can coexist and produce new creations in such fields.

This special issue on Nursing Robots and Support Systems for Welfare Sites includes one review paper and 23 other interesting papers that cover the following topics:

· Research on independence support and systems to watch over the elderly.

· Research on support systems for diet, recreation, medication, etc. for people with dementia.

· Research on control and sensor systems for vital signs and excretion.

· Research on rehabilitation equipment for the physically handicapped.

· Research on assistive technologies for mobility support.

· Research on upper and lower limb power assistance devices and robots.

We thank all authors and reviewers of the papers as well as the Editorial Board of the Journal of Robotics and Mechatronics for their help with this special issue.

The Japanese population is rapidly aging, with fewer proportion of children, and its production-age population has decreased correspondingly, with a resulting shortage in nursing-care service providers. To cope with this situation, the Japanese government has focused on developing and deploying nursing-care robots to compensate for the shortage of human resources. As most nursing-care services are intended for the elderly and disabled, they are traditionally considered as human services. To implement nursing-care robots on a large scale, numerous approaches and measures have been considered, such as modeling the approaches to effectively use nursing-care robots in nursing-care fields, rewarding highly useful nursing-care robots with greater nursing-care compensations, and responding to consultations at nursing-care sites by building a platform to develop, demonstrate, and deploy nursing-care robots. However, nursing-care services using robots are still not popular because of prevailing anxieties about and resistance to such technologies; therefore, the promotion of nursing-care services using robot technologies remains a challenge. Presently, a system capable of supporting not only a single nursing-care scenario but also a series of nursing-care operations is highly desired. In the future, nursing-care services have to be made more rewarding using robots, for which it is vitally important to provide support in the form of evidence-based, scientific, and effective nursing-care services.

In this study, the effect of social assistive robots (SARs) on the continuity of health management activities was verified through the measurement of daily grip strength. We proposed and developed an intervention system for grip strength measurement and installed it in a SAR. Then, 23 older adults used the system at home with and without a SAR. Each setup was applied for three weeks and the rates at which the participants forgot their daily grip strength measurements were compared at the end of the period. The rates at which the daily measurements were forgotten decreased significantly when a SAR was used. In particular, 9 participants were able to decrease their rate of forgotten measurements after they used a SAR. Thus, the SAR enabled the participants to regularly perform grip strength measurement activities. These findings indicate that appropriate intervention measures using SARs are effective in promoting the continuity of daily healthcare activities of older adults living at home.

Robot therapy, a mental health care through interactions with robots, has attracted attention as a new method of dementia care. In particular, the therapeutic seal robot named “PARO” is being widely used. When using PARO in elderly facilities, caregivers called “handlers” encourage the elderly people to interact with PARO. However, the usage of PARO was left to the handlers itself. Therefore, there was no intended effect in certain cases. To solve this problem, this study aims to develop a method to record the behaviors of handlers and the reactions of elderly people during the robot therapy and a method to support planning by analyzing the recorded data. A Bayesian network was applied to analyze the relationship between the handler’s behavior and the elderly people’s reactions. To verify usefulness, the experiment was conducted at four elderly facilities between November 2019 and January 2020. The participants were 12 handlers and 21 elderly people. We observed the robot therapy using PARO for 20 min, and subsequently, conducted interviews. Consequently, a model that visualized the relationship between the handler’s behaviors and the elderly people’s reactions was obtained from 40 observed cases. The interviews confirmed that the model was useful for planning a robot therapy.

Expectations for care robots are increasing owing to the aging of society with a declining birthrate and shortage of manpower in the care field. However, the use of care robots has not yet become widespread. In this study, we explained the artificial intelligence (AI) technology to care staff and conducted a questionnaire survey to understand their needs. Then, we began to develop a care robot that was required in the care field. In this paper, we report an overview and the current status of the study.

Medication is a key treatment for patients with schizophrenia. Patients with schizophrenia tend to easily decrease medication adherence with long-term treatment. However, there is a chronic shortage of specialists who provide medication support, such as visiting nurses. In addition, these patients do not often use smartphones or PCs in their daily lives. Thus, schizophrenic patients need a direct approach in the physical world because they are unfamiliar with cyberspace. This study aims to improve the home treatment environment using robot technology that can approach in the physical world of schizophrenic patients who need medication support. In this study, collaboration between psychiatric nursing specialists and medical engineers investigated the interaction between communication robots and patients. The results showed that the robot was accepted by patients with schizophrenia as a talking partner. The amount of robot talking seemed to affect the impression of the robot on schizophrenics. Utterance process analysis showed that the smoothness of the conversation affected the relationship between robots and schizophrenics.

We propose a system in which users can intuitively instruct the robot gripper’s positions and attitudes simply by tracing the object’s grasp part surface with one stroke (one drag) of the laser beam. The proposed system makes use of the “real world clicker (RWC)” we have developed earlier, a system capable of obtaining with high accuracy the three-dimensional coordinate values of laser spots on a real object by mouse-operating the time-of-flight (TOF) laser sensor installed on the pan-tilt actuator. The grasping point is specified as the centroid of the grasp part’s plane region by the laser drag trajectory. The gripper attitude is specified by selecting the left and right drag modes that correspond to the PC mouse’s left and right click buttons. By doing so, we realize a grasping instruction interface where users can take into account various physical conditions for the objects, environments, and grippers. We experimentally evaluated the proposed system by measuring the grasping instruction time of multiple test subjects for various daily use items.

In aging society like Japan, maintaining the quality of life (QOL) is an important objective. The oral cavity has various significant functions that contribute to the QOL. Elderly people are susceptible to the swallowing disorders owing to various factors associated with advancing age. In such cases, mealtime assistance can provide elderly persons appropriate eating situations. Thus, mealtime assistance skills are essential for students in nursing and caregiver education. Recently, simulation education has attracted attention as an effective educational process for nursing and caregiver students before their clinical practice in a hospital or care house. In this educational process, a patient model that mimics specific symptoms called the simulation model, is used to learn the symptoms and its care process in the same clinical environment as actual. We have attempted to develop several oral care simulation models, and we have earlier developed a prototype of mealtime assistance simulation model. This simulation model had a tongue model with a sensor system to detect spoon motions, and its fundamental functions were evaluated via spoon detection experiments. Based on the earlier achievements, in this study, we develop an evaluation system of feeding skill using a spoon. The pressing force and position by spoon on the tongue model were estimated by transfer functions derived from experiments. In addition, we developed an algorithm that leads students’ spoon position and pressing force in the correct position.

We investigated robot-assisted recreation (RAR) for improving the quality of life (QoL) of older adults with dementia in an aged care facility. However, as a simple method to evaluate RAR has not been established at the field level, limited scientific data exists to show its effectiveness. To solve this problem, we studied a method to evaluate RAR based on speech analysis, which can reduce the burden on subjects (older adults) and data analysts. This study conducted both subjective and objective analyses of speech data. Subjective analysis based on the transcripts of speech data resulted in findings that supported and added to the knowledge of previous research, such as an increased willingness to participate in RAR, positive feelings toward the future, and interest in interacting with others. The results of the objective analysis based on the fundamental frequency (F0) demonstrated that there was a difference in the distribution of F0 during RAR and the interviews conducted before and after RAR. This study thus provides the prospect for easy evaluation of recreational activities, including RAR, in aged care facilities at the field level using speech analysis.

In recent years, robotic pets have been used by many countries worldwide as a method for treating behavioral and psychological symptoms of dementia (BPSD). The seal robot PARO was loaned intermittently to a distributed layout elderly housing with services over a seven-month period, during which it was observed that three residents with cognitive dysfunctions showed improvements in their BPSD and the nursing care load of the staff was reduced during the periods when PARO was present. The objective of this study is to investigate, through a case study, the effects of intermittent interaction with PARO on those with cognitive dysfunctions and the staff workers. The short version of the Dementia Behavior Disturbance Scale (DBD-13) was used as the medical outcome index, and the KJ method was used to analyze the qualitative data, such as staff reports and interviews. The results show that the DBD-13 total scores reduced during the periods when PARO was present and increased during the periods when PARO was absent. The KJ method yielded similar findings. The use of DBD-13 and the KJ method complemented the results of each other and increased the persuasive power of the findings. By using the KJ method, it was further determined that the workload of the staff was reduced, allowing them to recuperate, which reconfirmed the value of PARO. Further case studies will be undertaken in the future with the aim of constructing a methodology for implementing case studies.

Patients who have lost vocal cord function due to laryngeal cancer or laryngeal injury are incapable of speech because it is impossible to generate the laryngeal tone from which the voice originates. For such patients, various speech production substitutes have been devised and put into practical use. The electrolarynx is one of these speech production substitutes and it can be used with relative ease. However, the sound is sometimes difficult to hear and its quality is monotonous. Therefore, focusing on the control method to improve the articulation of the electrolarynx, we have proposed an electrolarynx controlled by myoelectric signals of the neck. The sternohyoid muscle, which is located in the superficial layer of the neck, was the source of the myoelectric signals. This muscle is active during speech, and its activity increases mainly at the time of speech in a low voice. We succeeded in detecting the surface myoelectric signals of the sternohyoid muscle and performing on/off control of the electrolarynx by signal processing. This report includes the derivation of a control function for converting into a control signal of the fundamental frequency of the electrolarynx from the relationship between the myoelectric signals and the fundamental frequency of the voice. This report also includes an evaluation of the controllability of the electrolarynx by comparing the obtained control signal with the user’s intention. Regarding the control of the fundamental frequency, we have proposed a method of control in three stages – high, medium, and low – and a method of control in two stages – high and low – and compared their performances. The results of the three-stage control indicated that the use of the logarithm as a control function for converting the myoelectric signals into the fundamental frequency of the electrolarynx succeeded in the control at an accuracy of 90% or more by changing the pitch of the generated sound depending on the subjects. It was also indicated that the error rate was as low as less than 20%, while maintaining a constant sound. This makes it clear that the use of the logarithm as a control function gives the highest controllability. The two-stage control exhibits a very high control success rate exceeding 90%, regardless of the type of control function; in particular, the control function using the logarithm exhibits a control success rate exceeding 95%. These results indicate that the electrolarynx control function obtained using the logarithmic function has excellent controllability.

In this study, we report on the development and evaluation of new excretion detection devices based on an existing product, Product H, which utilizes odor-sensing technology. Caregivers can use the developed device to receive a detection signal and record the true/false status of the detection. This device is based on a preliminary interview with caregivers regarding the desirable characteristics of the planned device. As a result, the size of the device was reduced to approximately 20% of the existing product. An excretion detection rate of 60% was achieved in a clinical experiment, as compared with that of 80% for Product H. This is significant because the parameter values were not yet optimized for the developed device. Further, a simple questionnaire was administered to caregivers, in which the intuitiveness of the operation and the functionality of the design were praised. However, there is a desire for an option to record more excretion characteristics was expressed. Therefore, we developed a revised device to include an input option regarding the amount and hardness of the excrement. The results of the subsequent evaluation questionnaire on the revised device were mostly favorable, but the caregivers had divided opinions on the new input feature. This result suggests a need for further investigation regarding the necessity of this feature.

Measurement of the sleeping state is useful for monitoring the health of a person being nursed. The sleeping state can be estimated from biological information such as respiration rate, heart rate, body motion, and lying posture. A heart rate measurement method that considers the harmonics of a respiratory signal is described herein. The harmonics of respiratory signals for heart rate measurement has not been considered hitherto. An unconstrained method is proposed for measuring respiration, heart rate, and lying posture using a Smart Rubber sensor, which is a rubber-based flexible planar tactile sensor developed for this study. Respiration and heart rates are measured by applying frequency analysis to time-series data of body pressure. The harmonics of a respiratory signal serves as noise in heart rate measurement. Therefore, the heart rate measurement is improved by eliminating the effects of harmonics. The average frequency error of the heart rate measurement by our proposed method is 0.144 Hz. Experimental results show that our proposed method enhances the precision of heart rate measurement. Hence, this method enables the accurate measurement of the sleeping state.

Human-machine cooperative robots are required to drive their arms with low impedance and high torque. As a compact mechanism that generates a large torque and has low impedance characteristics, the series elastic drive system, in which an elastic element is inserted between the motor and driving unit, has been proposed. In this paper, we propose a method of applying impedance control to a series elasticity system with a torque-compensating motor that uses a torsion bar as an elastic body that enables its use under high loads. The stability of the system was verified via simulation and experiment by considering the allowable speed and maximum torque of the motor. The experimental results from the conventional system and the proposed system were compared. The proposed system was confirmed to be superior to the conventional system in terms of both stability and tracking performance. Consequently, the effectiveness of our proposed system was confirmed.

This paper proposed an ankle joint stretching device that is intended for self-rehabilitation by using a tension rod structure. Physical therapists treat their patients to prevent a subject ankle joint’s contracture and improve walking function. Still a sufficient rehabilitation therapy cannot be done due to demand for a labor-task of the ankle joint rehabilitation. There is a demand for the self-rehabilitation system long time to reduce the labor task, and especially it can be installed easily in a chair or bed in a patient home. By using a pantograph jack and spring casters, the developed device does not depend on installation location. It does not need a transfer assist process to the rehabilitation machine, which causes back pain of caregivers, and it allows for a self-rehabilitation of an ankle joint stretching. The experiment confirmed that the positional relationship was stabilized between the rotation axis of the device and the ankle joint position within (σ_x,σ_y)=(2.4, 2.5) mm during ankle dorsiflexion stretching in a fixed state of the device, which was realized by the pantograph jack and spring casters. Our proposed system that does not need transfer assistance before/after treatment will lead to self-rehabilitation for the ankle joint.

Various control systems for robot arms using surface myoelectric signals have been developed. Abundant pattern-recognition techniques have been proposed to predict human motion intent based on these signals. However, it is laborious for users to train the voluntary control of myoelectric signals using those systems. In this research, we aim to develop a rehabilitation support system for hemiplegic upper limbs with a robot arm controlled by surface myoelectric signals. In this study, we construct a simple one-link robot arm that is controlled by estimating the wrist motion from the surface myoelectric signals on the forearm. We propose a training scheme with gradually increasing difficulty level for robot arm manipulation to evoke surface myoelectric signals. Subsequently, we investigate the possibility of facilitative exercise for the voluntary surface myoelectric activity of the desired muscles through trial experiments.

While an aging population in Japan and other countries is resulting in an increased demand for nursing care services, there is a shortage of care workers due to a decrease in the working population. The use of care assistive technologies such as robots, artificial intelligence, and information technology is expected to compensate for this shortage, and many care assistive technologies such as power assist devices and communication robots have been developed. However, their introduction and widespread use in actual service have not progressed. The aim of this study is to address the problem on less technology introduction in nursing care by surveying the attitudes of potential users to care assistive technologies, clarify the factors affecting the use of such technologies, and propose a new design method for the technologies. We surveyed attitudes to the use of care assistive technology from the perspective of function and information utilization for three groups: active seniors, informal carers, and formal carers. The survey was conducted in Japan and Finland, which have high aging populations. Based on the survey results, we proposed, as a design method, a classification of care assistive technologies according to their interaction with users as well as the nursing care process.

Human standing stability was evaluated using a swash plate drop device in a disturbance application. Under different experimental conditions using the device, electromyogram (EMG) measurements showed that the left and right lower limb muscles were used differently. It also demonstrated that the dynamics also differed depending on the experimental conditions. In particular, the dynamics of standing stabilization in a tandem standing position and a normal standing position significantly differed, and the activities of related muscles were also significantly different; this indicates that standing stability may potentially depend on the subjects. These results indicate the need for the comprehensive consideration of the standing and disturbance conditions during the quantitative evaluation of human standing stability.

A tele-rehabilitation system that can achieve remote interaction between a physical therapist (PT) and a patient was developed. Patients need to execute rehabilitation exercises to maintain upper limb function. However, it is difficult for them to travel to hospitals without aid. This system is equipped with a PC and a Kinect sensor at the hospital side (i.e., the PT), and a PC and an upper limb assistive device in the patient’s home. The PT displays the motion in front of a Kinect sensor, which identifies the motion. In addition, the device on the home side assists the motion of the patient using the Internet. When the device receives a force higher than the safety value from the patient at any particular point on it, vibrators at the corresponding point on the PT’s arm start to vibrate. Thereby, the PT can identify the patient’s condition and limitations. The time delays in the transmission of data of device motion and the vibrators were measured and compared. As a result, the PT could identify the patient’s condition faster than the motion of the device.

The risk of disuse syndrome caused by prolonged supine posture in hemiplegic stroke in- and outpatients has become a social problem. This study aimed to develop a new bed with a standing-up function, allowing medical caregivers and patients to freely take a standing position on the bed to reduce the amount of time spent in the supine position and to clarify its effectiveness through evaluation of its usability and clinical use. In addition to the Gatch function of the developed bed, it allows transition from a supine position to a chair-sitting or standing position on the bed, and from a standing position to walking action. In addition, as with the tilt table used for standing-position training, the bed’s tilt angle can be adjusted, reducing the load on the lower limbs and allowing appropriate rehabilitation to be carried out anytime, consequently reducing the burden of nursing care. The bed was developed with the cooperation of a specialized bed manufacturer and supported by public funds, and clinical evaluation was conducted after confirming its safety. We evaluated the physical and physiological functions of two hemiplegic patients after 4 weeks of standing training using a prototype bed, to which results from the six-item test showed no significant improvement. However, medical professionals, such as doctors, nurses, and physical therapists, who participated in the clinical evaluation indicated that the bed can safely replace the tilt table for standing-position rehabilitation, and it is effective in eliminating related human and time burdens.

When assisting a care receiver to transfer from one plane to another, a caregiver needs to hold up and move him/her. As a caregiver has to support the weight of one person, transfer assistance imposes a heavy physical burden on the caregiver. Particularly, in Japan, with an increasing elderly population and a decreasing young population, there are a few caregivers to assist numerous care receivers to transfer. In this scenario, it is an extremely vital issue to develop methods to reduce the burden of the caregivers when assisting care receivers to transfer. In this study, by focusing on the clothes that care receivers wear, we developed a transfer-assisting robot system by combining a dedicated posture-supporting wear and a mobile robot based on a lift mechanism.

In this paper, an indoor robotic walking care device to assist the daily activity of the elderly is proposed. The proposed robotic walking care device was designed to provide support for daily activities, especially standing-sitting, walking, and toileting, based on the concept of the International Classification of Functioning and a modified V-shaped process while accounting for human-machine interactions. A prototype of the proposed device was designed and built on the basis of the concept, which implemented power assisting wheels and a lifting device. Risk assessments for different use cases and risk reduction measures against possible hazards were conducted using a three-step method to ensure safety while using the device. The validity of the proposed device was quantitatively verified through preliminary tests of standing-sitting, walking, and toileting motions in a care facility.

Rolling walkers are popular mobility aids for older adults. A rolling walker usually has two swivel front wheels and two non-swivel rear wheels. It is designed to improve stability while walking and reduce the risk of falling. However, a considerable number of users have come close to or experienced falling. We developed a user-adaptive brake assist system for the walker. In the system, the usage of a walker is modeled in combination with the walking speed and the distance from the walker to the user. A brake pattern is generated based on usage data interpolated using the inverse distance weighting method. The pattern is referenced to activate brakes with the corresponding strength while walking. The applicability was confirmed by analyzing the walking data of two older adults, and the usability was positively evaluated in experiments with seven young adults wearing elderly simulation suits.

In this study, we propose a method to estimate the assistive timing requirements for a power-assisted lumbar suit based on upper-body acceleration. Our developed power-assisted suit combines of springs, wires, and an electrical motor to provide efficient assistance. The assistive torque provided by the suit was determined based on a digital human model. The assistive timing using the electrical motor was calculated from the upper-body acceleration measured using two internal accelerometers. Herein, we present the experimental results based on the myoelectricity of a muscle during lifting motions involving three participants acting as caregivers to elderly patients.

In Japan, approximately 1.1 million people suffer from cerebrovascular diseases such as cerebral stroke, which can further increase due to the aging society. Therefore, rehabilitation for the physical recovery of patients with hemiplegia caused by cerebrovascular disease plays an important role in maintaining and improving their quality of life (QoL). In rehabilitation facilities, crutches and parallel bars are the mainstream, but patients support their body with their arms, causing falls and fatigue, leading to deterioration of motivation in long-term rehabilitation. Although a few hanging-type devices have been developed to cope with such issues, they occupy large space, require time to wear, and have a high introduction cost. In this study, we developed a non-wearing-type pneumatic power assist device for gait rehabilitation to ensure patients can sustain their body weight by pushing up their armpit and quantitatively verified the effectiveness of the device.

Automation in the food industry is not as developed as in the automotive industry because of difficulties in handling food products with large variations in shape, size, and mechanical properties. In this paper, a pneumatic-driven soft needle gripper is proposed for handling food materials. It was constructed using a soft membrane and multiple rigid needle-like fingers. It can work under two operational modes: grasping and piercing. The grasping mode can be used to grasp shredded and chopped food materials. The piercing mode is for handling food products when only the top surface of the food product is available for handling. The needle gripper is fabricated using a multi-material 3D printer. Experimental tests on various food materials are conducted to validate grasping and piercing operations. The results of grasping tests suggest that the needle gripper can successfully grasp shredded and chopped food materials. A quantitative analysis shows that the relative standard deviation of the grasped food weight was within 20%. Although the results of piercing tests validate that the needle gripper can successfully handle various food materials, releasing the food materials involves certain difficulties.

The path planning problem of logistics robots is mainly subjected to the time cost of the operation of the mathematical model. To save the time of refilling process in the fast medicine dispensing system (FMDS), the optimization procedure is divided into two steps in this study. First, a new mathematical model called the multiple steps traveling salesman problem model (MTSPM) is proposed to optimize the replenishment quantity of each picking and establish picking sets. Second, an improved ant colony optimization (IACO) algorithm is employed, considering the effects of velocity, acceleration, and deceleration in the refilling route during the development of the new model. Simulation results and operational results demonstrated that MTSPM-IACO was better than both the order picking model (OPM) and MTSPM-ACO in terms of saving refilling time. Compared to the OPM, the optimization of the refilling time of MTSPM-IACO was more than 1.73% in simulation and 15.26% in operation. Compared to MTSPM-ACO, the optimization of the refilling time of MTSPM-IACO was more than 0.13% in simulation and 1.67% in operation.

Over the past few decades, biologists and engineers have attempted to elucidate the swimming mechanism of fish and developed a fish-like robot to perform fast swimming in water. Such a robot will have wide applicability in investigations and exploration in the sea. There have been many studies on fish-type robots; however, the propulsion efficiency of the introduced robots is far from that of the actual fish. The main reason is that the robot controller for generating motions is conventionally designed by trial and error, and little attention has been placed on designing a motion controller that matches the body structure of a real fish. In this paper, we present an approach that uses fin-curvature-based feedback to design a motion controller. A swimming robot composed of a body with two actuated joints and a flexible tail fin is developed. After examining the relationship between the swimming speed and tail fin curvature in feedforward (open-loop) system experiments, we propose to reflect the tail fin curvature to the actuation inputs (phase difference between the two cyclic oscillations), which will perform the efficient swimming motion. Further, the results show that implementing the proposed feedback controller in a fish-type robot makes it swim similar to a real fish. In addition, the proposed controller functions to find inappropriate actuation according to the body structure.

Dielectric elastomer actuators (DEAs) are a promising technology for soft robotics. The use of DEAs has many advantages, including light weight, resilience, and fast response for its applications, such as grippers, artificial muscles, and heel strike generators. Grippers are commonly used as grasping devices. In this study, we focus on DEA applications and propose a technology to expand the applicability of a soft gripper. The advantages of gripper-based DEAs include light weight, fast response, and low cost. We fabricated soft grippers using multiple DEA layers. The grippers successfully held or gripped an object, and we investigated the response time of the grippers and their angle characteristics. We studied the relationship between the number of DEA layers and the performance of our grippers. Our experimental results show that the multi-layered DEAs have the potential to be strong grippers.