Abstract
Artificial Active Antenna is a new family of sensing system that can detect the contact location between an insensitive flexible beam and an environment through the measurement of the rotational compliance of the beam in contact with the environment. This paper discusses the 3D Active Antenna composed of an insensitive flexible beam, two actuators to move the beam in 3D space, two position sensors to measure the actuator position, and a two-axis moment sensor to evaluate the contact force. The lateral slip, which is the inherent characteristic for 3D Active Antenna, strongly depends on the pushing direction, the friction at the point of contact, and the normal surface of environment where the antenna makes contact. Generally, such a lateral slip overestimates the rotational compliance, deteriorates the sensing accuracy directly. In this paper, we discuss how to detect the lateral slip by using the sensors implemented and how to determine the next pushing direction for avoiding the lateral slip. We show that the two-axis moment sensor is effectively utilized for detecting the lateral slip. We propose a sensing algorithm which eventually lead to the pushing direction providing the exact contact distance. We also show a practical approach enabling us to detect the contact distance with permissible sensing accuracy, by at most three active motions.
