def cmd_gimbal(self, args):
        '''control gimbal'''
        usage = 'Usage: gimbal <rate|point|roi|roivel|mode|status>'
        if len(args) == 0:
            print(usage)
            return
        if args[0] == 'rate':
            self.cmd_gimbal_rate(args[1:])
        elif args[0] == 'point':
            self.cmd_gimbal_point(args[1:])
        elif args[0] == 'roi':
            self.cmd_gimbal_roi(args[1:])
        elif args[0] == 'mode':
            self.cmd_gimbal_mode(args[1:])
        elif args[0] == 'status':
            self.cmd_gimbal_status(args[1:])
        elif args[0] == 'roivel':
            self.cmd_gimbal_roi_vel(args[1:])