  In multi-point contact systems, precise force control is crucial for
achieving stable and safe interactions between robots and their environment.
Thus, we demonstrate an admittance controller with auto-tuning that can be
applied for these systems. The controller's objective is to track the target
wrench profiles of each contact point while considering the additional torque
due to rotational friction. Our admittance controller is adaptive during online
operation by using an auto-tuning method that tunes the gains of the controller
while following user-specified training objectives. These objectives include
facilitating controller stability, such as tracking the wrench profiles as
closely as possible, ensuring control outputs are within force limits that
minimize slippage, and avoiding configurations that induce kinematic
singularity. We demonstrate the robustness of our controller on hardware for
both manipulation and locomotion tasks using a multi-limbed climbing robot.
