diff --git a/api/zi_xymotor.hpp b/api/zi_xymotor.hpp
index 963bf9e..8492a94 100644
--- a/api/zi_xymotor.hpp
+++ b/api/zi_xymotor.hpp
@@ -10,12 +10,12 @@ using namespace std;
 class ZIXYMotor {
  public:
   virtual ~ZIXYMotor() {}
-  virtual int32_t xymotor_enable(int32_t enable)                                  = 0;
-  virtual int32_t xymotor_move_by(int32_t dx, int32_t dy, int32_t motor_velocity) = 0;
-  virtual int32_t xymotor_move_to(int32_t x, int32_t y, int32_t motor_velocity)   = 0;
-  virtual int32_t xymotor_move_to_zero()                                          = 0;
-  virtual int32_t xymotor_read_pos(int32_t *x, int32_t *y)                        = 0;
-  virtual int32_t xymotor_set_pos(int32_t x, int32_t y)                           = 0;
+  virtual int32_t xymotor_enable(int32_t enable)           = 0;
+  virtual int32_t xymotor_move_by(int32_t dx, int32_t dy)  = 0;
+  virtual int32_t xymotor_move_to(int32_t x, int32_t y)    = 0;
+  virtual int32_t xymotor_move_to_zero()                   = 0;
+  virtual int32_t xymotor_read_pos(int32_t *x, int32_t *y) = 0;
+  virtual int32_t xymotor_set_pos(int32_t x, int32_t y)    = 0;
 
   virtual int32_t xymotor_motor_move_by_direct(int32_t motor1_dpos, int32_t motor2_dpos) = 0;
   virtual int32_t xymotor_read_enc_direct(int32_t *enc1, int32_t *enc2)                  = 0;