A direct pose feedback (DPF) control method applied to a DPF controlled machine is provided. The DPF control method includes a pose compensation control in addition to the position feedback control. The pose compensation control includes an initiation step, a reference system step, an actual pose calculation step and a position compensation step. The sum of the primary driving value and the compensation driving value is output to the driver of each of the motors. The advantage of the DPF control method is that the existing real-time position control loop in the controller can remain unchanged, while the pose compensation control is added to eliminate tool pose error resulted from geometric errors in the machine. The DPF controlled machine uses a pose measuring mechanism to measure the actual pose of the tool and to compensate the tool pose error. Hence, the DPF controlled machine is free of geometric errors.

The method can include measuring the tridimensional positions of a reference feature for a first at least three different angular positions of the reference feature around the first rotation axis and a same first reference angular position around the second rotation axis, the reference feature being fixed relative to the component; and measuring the tridimensional positions of the reference feature for a second at least three different angular positions of the reference feature around the first rotation axis and a same second reference angular position around the second rotation axis.

A measuring apparatus for measuring a planar relative motion between a tool attacher and a work attacher of a machine tool includes at least one image capturing element capable of performing image capturing at a first position, a second position, and a third position, which are not located on the same line. The image capturing elements at the first position, the second position, and the third position are caused to capture a first point, a second point, and a third point, respectively, arranged on at least one plane of an XY-plane, an XZ-plane, and a YZ-plane. The image capturing element at the second position and the image capturing element at the third position are caused to capture the first point, the image capturing element at the first position and the image capturing element at the third position are caused to capture the second point, and the image capturing element at the first position and the image capturing element at the second position are caused to capture the third point. Based on the image capturing result, a value indicating the planar relative motion between the tool attacher and the work attacher is calculated.

A direct pose feedback (DPF) control method applied to a DPF controlled machine is provided. The DPF control method includes a pose compensation control in addition to the position feedback control. The pose compensation control includes an initiation step, a reference system step, an actual pose calculation step and a position compensation step. The sum of the primary driving value and the compensation driving value is output to the driver of each of the motors. The advantage of the DPF control method is that the existing real-time position control loop in the controller can remain unchanged, while the pose compensation control is added to eliminate tool pose error resulted from geometric errors in the machine. The DPF controlled machine uses a pose measuring mechanism to measure the actual pose of the tool and to compensate the tool pose error. Hence, the DPF controlled machine is free of geometric errors.

The method can include measuring the tridimensional positions of a reference feature for a first at least three different angular positions of the reference feature around the first rotation axis and a same first reference angular position around the second rotation axis, the reference feature being fixed relative to the component; and measuring the tridimensional positions of the reference feature for a second at least three different angular positions of the reference feature around the first rotation axis and a same second reference angular position around the second rotation axis.

A measuring apparatus for measuring a planar relative motion between a tool attacher and a work attacher of a machine tool includes at least one image capturing element capable of performing image capturing at a first position, a second position, and a third position, which are not located on the same line. The image capturing elements at the first position, the second position, and the third position are caused to capture a first point, a second point, and a third point, respectively, arranged on at least one plane of an XY-plane, an XZ-plane, and a YZ-plane. The image capturing element at the second position and the image capturing element at the third position are caused to capture the first point, the image capturing element at the first position and the image capturing element at the third position are caused to capture the second point, and the image capturing element at the first position and the image capturing element at the second position are caused to capture the third point. Based on the image capturing result, a value indicating the planar relative motion between the tool attacher and the work attacher is calculated.