Isotropic velocity radius (IVR) and isotropic accelerationradius (IVR) are proposed as local performance indices to quantify thedynamic responsiveness of a multi-arm robot as regards the velocity effects.These performance measures are defined on the basis of the acceleration setdescribing the effects of actuator torques, velocity of the manipulated object,and gravity upon the acceleration of the object. An algorithm is presented toobtain an explicit expression for calculating these measures by decomposing thetorque-related non-square matrix into square matrices without using the conceptof pseudo-inverse for the planar multi-arm robot composed of arms each with twojoints.

Numerical examples for a planar robot with two 2R arms show thatthe proposed concepts are effective in representing the acceleration capabilityand velocity effects of a multi-arm robot.