Several interesting experiments have been carried out on the self-constructed dual-arm robot to verify the effectiveness of the proposed design. We first show the feasibility of the motion planning strategy for transforming dual-arm in grasping mode and supporting mode. Then we demonstrate and evaluate the correctness of compliance motion and obstacle avoidance in robot walking assist.
B. Obstacle avoidance controller
To prevent from colliding with objects in the environment
during walking assist, we add an obstacle avoidance function
to the mobile platform. The distance data are provided from
laser range finder equipped on the front side of the robot. We
define nine scanning ranges. Each range covers 20 degree.
The segmentation of laser sensing area is shown in Fig.8. We
set the robot heading in range 4 to range 6 and use the judge
method shown in (3) to calculate the angle velocity of
obstacle avoidance. The distance data of range 3 and range7
are used to judge the direction of turning. As shown in (4), the
angular velocity of the mobile robot is determined by the
acquired distance data from laser scanner and the amount of
turning is related to the distance and heading relative to the
obstacle. Note that only the angular velocity is controlled in
obstacle avoidance, the linear velocity, which is determined
by the compliance controller of the robot, is not influenced.