PURPOSE: To provide stable control with quick response irrespective of load by presuming the load on the foremost shaft varied by object grasping from the dynamic characteristic, and by calculating the control parameter.

CONSTITUTION: A presuming part 1 is fed with drive torques on the shafts given by a controller 4 and the position (q) and speed (q') from a robot 2 and determines the presumptive value of unknown parameter. If given a load exist signal, a calculating part 3 calculates a control parameter from the input presumptive value for load by the use of an equation of control parameter vs. the predetermined load. This calculated value is fed into the controller 4 to provide adaptation of the control parameter. Thus change in the load will vary the parameter of robot part, and the control parameter is determined through presumption using this robot part parameter, so that control parameter can be obtained in good compliance to varying load.