1. A robot, comprising: a dynamical system including: a plurality of rigid links; joints pivotally connecting pairs of the rigid links, wherein the robot has a number of degrees of freedom (DOFs); and an actuator associated with each of the joints, whereby the robot is fully actuated; a constraint positioned relative to the dynamical system to apply force upon the dynamical system thereby limiting vertical or horizontal motion of the dynamical system beyond a predefined position; and an operational space controller comprising a constrained task space dynamics module and a constrained null space dynamics module both concurrently providing control signals to drive the actuators to operate the robot to perform a task, wherein the control signals generated by the constrained task space dynamics module each defines a torque associated with the robot performing the task and wherein the control signals generated by the constrained null space dynamics module each defines a torque that is irrelevant to the robot performing the task.