This paper presents a self collision detection scheme for humanoid robots using elliptical and circular capsules as bounding volumes. A capsule is defined as an elliptical or circular cylinder capped with ellipsoids or spheres respectively. The humanoid body is modeled using elliptical capsules, while the moving segments, i.e. arms and legs, of the humanoid are modeled using circular capsules. This collision detection model provides a good fit to the humanoid body shape while being simple to implement. A case study of the self collision free workspace of the humanoid arm is then presented to illustrate the effectiveness of the collision detection scheme.

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Mobile manipulators are highly susceptible to tip over due to the motion of the manipulator or the gradient of the slope being traversed by the robot's mobile base. This paper presents the experimental validation of the tip over stability analysis of a tracked mobile manipulator. The Force Angle stability measure is used to compute the stability index of the platform. A refined model of a tracked mobile manipulator is used to determine the ground contact points which form an input into the stability formulation. A Vicon motion capture system is used to determine the actual time of tip over of the robot. It is found that the tip over model is able to determine the tip over occurrence ahead of the actual tip over time in the majority of the test cases.

This paper presents a self collision avoidance scheme for humanoid robots using elliptical and circular capsules as collision bounding volumes. A capsule is defined as an elliptical or circular cylinder capped with ellipsoids or spheres respectively. The humanoid body is modeled using elliptical capsules, while the moving segments, i.e. arms and legs, of the humanoid are modeled using circular capsules. The self collision distance between two capsules is computed and used to generate self collision free motion of the humanoid. Collisions are avoided by adjusting the joint angles of the colliding segments based on the collision distance and the location of the collision points. A case study of a humanoid dance is used to test the self collision avoidance method. Self collision free motion is attained by the humanoid for the entire dance.