Abstract
The present paper deals with an automatic measuring method with a three-dimensional coordinate measuring machine for the foot. The objective in measuring foot shape is to design a good shoe model to make fitted prosthetic devices and to evaluate foot shape in orthopedic surgery and rehabilitation fields. To measure a soft and complicated object like a foot, a measuring method with a three-dimensional coordinate measuring machine yields good results. We developed a new micro-computer-based measuring system which can measure any complicated object exactly and automatically, can operate the measured shape to match many purposes and can manufacture that positive or negative model. Therefore, this system can be called a CAD/CAM system for the living body. This measuring machine has five axes (three degrees of freedom and a rotation structure for its sensor probe with two degrees of freedom). A capacitance-type touch sensor with a needle probe is used to obtain an ON/OFF touch signal. The main problem is how to measure a foot automatically. For such a complicated object, control of five axes is very difficult. A new automatic measuring method measures a foot model with simple measuring probe path data and then generates optimized path data. With that data, a foot can be measured automatically and efficiently. The next problem concerns data operation. One of the merits of this system is that it expresses a measured shape with numerical three-dimensional values. A connecting index to connect the measured parts smoothly and a bending curve to correct the measured shape have been developed. These are fundamental methods for the living body. With these measuring and data operating methods, a foot shape can be measured, and various shape operations can be done freely. To make a good shoe model or a fitted prosthetic device, the most important thing is to measure foot shape exactly and fully, with useful operating methods. Now these fundamental methods have been developed. This system is quite useful in shortening design time, because designs are fine tuned numerically, and can be optimized without constructing a test model.
