A Pragmatic Approach to Exploiting Full Force Capacity for Serial Redundant Manipulators

Maximising Wrenches for Kinematically Redundant Systems with Experiments on UVMS

“…Wrench polytope analysis has been used extensively in the design and evaluation of manipulators and manipulator poses [19], [20], yet optimisation is difficult since the quality of a polytope is difficult to quantify. Some attempts to define capability measures using polytopes involve computing actuator saturation for a given wrench direction for serial manipulators [6], or solving Linear Programming (LP) problems for parallel manipulators [21], [22].…”

“…Redundancy parameterisation has been used for choosing optimal stiffness configurations in serial manipulators with one degree of redundancy [23], as well as for exploring the force capabilities of a manipulator to apply forces normal to a surface [24]. This work was extended in [6] to an exhaustive search over 2 redundant DOF for a 7DOF manipulator, where the saturating wrench was used to find the weight lifting capability for each pose, while [25] examined a planar parallel manipulator with a 3DOF redundant space to minimise the sum of squared joint torques for a given wrench. Given an appropriate parameterisation of the redundant DOF written as θ r ∈ R n−6 , Equation 4 can be re-written as…”

“…External contact forces and torques between the end effector and the environment are transmitted through each DOF of the system responsible for end effector motion, in a way which is highly dependent on the configuration. Exploiting the continuous redundancy offered by high DOF systems allows for configurations which simultaneously achieve a desired end effector pose, and maximise the wrench capabilities [6].…”