Linking apparatus control device

Patent metadata

Field	Value
Publication number	US-2016008977-A1
Application number	US-201514864412-A
Country	US
Kind code	A1
Filing date	Sep 24, 2015
Priority date	Mar 26, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

A control device is provided which is operable to change the position of a distal end side link hub by driving each of arms, which are proximal end side links of a plurality of link mechanisms by means of an actuator. When in a series of operations, the position change of the distal end side link hub is mad by an angle greater than a predetermined angle, a relay position setting unit is provided for setting a relay point between a starting point and a terminating point of each of the arms so that the interference of the three axis arms may be relieved. A position change control unit performs a position control so as to pass simultaneously through the relay point so set.

First claim

What is claimed is:

1 . A control device for a link actuator to control each of actuators of the link actuator in such a manner as to change position of a distal end side link hub relative to a proximal end side link hub from a starting point position towards a terminating point position which is commanded, in which the link actuator includes
three or more link mechanisms that connect the distal end side link hub to the proximal end side link hub in a position-changeable fashion, each link mechanisms including a proximal side end link member, one end of the proximal side end link member being pivotably connected to the proximal end side link hub; a distal side end link member, one end of the distal side end link member being pivotably connected to the distal end side link hub; and an intermediate link member with its opposite ends pivotably connected to the other ends of the proximal side end link member and the distal side end link member, respectively, each of the link mechanisms having such a shape that a geometric model of the link mechanism represented by lines shows symmetry between a proximal end side portion thereof and a distal end side portion thereof with respect to a center portion of the intermediate link member, and each link mechanisms being provided with the actuator that arbitrarily changes position of the distal end side link hub relative to the proximal end side link hub by rotating the proximal side end link member in the form of the arm, the control device comprising: a position change control unit to drive each of the actuators in synchronism with each other on a point-to-point basis from a starting point, which is the rotational angle of the arm when the starting point position is assumed, to a terminating point which is the rotational angle when the terminating point position is assumed; a relay position setting unit configured to compare a position changing amount of the distal end side link hub in the position change from the starting point position to the terminating point position with a predetermined amount, and configured to, in the event that the position changing amount of the distal end side link hub is larger than the predetermined amount, set one or more relay position according to a predetermined rule during the course of an position changing path for changing from the starting point position to the terminating point position and to set by determining a rotational angle which corresponds to a relay point of the rotational path of each of the arms when the relay position is assumed, wherein the position change control unit performs a position control so that each of the arms simultaneously passes through the relay point set by the relay position change setting unit.

2 . The control device for the link actuator as claimed in claim 1 , wherein the relay position setting unit divides the rotational amount of each of the arms on the basis of a division number by which the position change amount of the distal end side link hub from the starting point position to the terminating point position is divided into an amount smaller than a predetermined amount.

3 . The control device for the link actuator as claimed in claim 1 , wherein three link members are provided and the relay position setting unit sets the relay point according to the rule, the rule including: selecting two arms out of the three arms which operate during the course of changing the position from the starting point position of the distal end side link hub to the terminating point position; equally dividing the rotational path of the selected two arms; and setting the position of the remaining one arm at a position uniquely determined according to a relative positional relationship with the other two arms.

4 . The control device for the link actuator as claimed in claim 3 , wherein as a criterion for selecting the two arms out of the three arms, the arms having large rotational amounts are selected.

5 . The control device for the link actuator as claimed in claim 3 , wherein the position (θ, φ) of the distal end side link hub is determined from the rotational angle of the selected two arms by a transformation equation of forward transformation, and the rotational angle of the remaining one arm is determined by a transformation equation of inverse transformation from the position (θ, φ) of the distal end side link hub.

6 . The control device for the link actuator as claimed in claim 5 , wherein the position (θ, φ) of the distal end side link hub is determined by a convergence calculation with the use of the rotational angle of the two arms out of the three arms and a transformation equation.

7 . The control device for the link actuator as claimed in claim 1 , wherein the relay position setting unit utilizes the predetermined rule for determining the relay point of each of the arm, and in the rule one or more relay positions on a path through which the distal end side link hub moves in the shortest distance and sets the rotational angle of each of the arms to be the relay point, the rotational angle corresponding to the position (θ, φ) of the distal end side link hub on the path, which position is any one of the starting point position, the relay position and the terminating point position on the path and the value achieved between the neighboring positions attains a value smaller than a predetermined value.

8 . The control device for the link actuator as claimed in claim 7 , wherein the rotational angle of each of the arms is determined from the position (θ, φ) of the distal end side link hub by means of the transformation equation of inverse transformation.

9 . The control device for the link actuator as claimed in claim 1 , wherein three link mechanisms are provided, and, from the starting point position (θa, φa) and the terminating point position (θb, φb) of the distal end side link hub, the position (θ 1 , θ 2 , . . . θn, φ 1 , φ 2 , . . . φn) (wherein n is equal to the division number minus 1) of each of the distal end side link hubs, in which the moving amount Δθ of the bending angle θ and the moving amount Δφ of the pivot angle Δθ attains a value smaller than a predetermined moving amount, is determined according to the transformation equation of inverse transformation and the position (θ 1 , θ 2 , . . . θn, φ 1 , φ 2 , . . . φn) of the distal end side link hub so determined is set to be the relay position.

10 . The control device for the link actuator as claimed in claim 1 , wherein the position change control unit performs a positional control from the starting point position of the distal end side link hub to the terminating point position thereof without acceleration and deceleration over the entire zone except for an acceleration zone, in which the position change starts from the starting position, and a deceleration zone in which deceleration takes place immediately before the terminating point position is attained.

11 . The control device for the link actuator as claimed in claim 1 , wherein, assuming that in the link actuator a connecting end axis of the intermediate link member, which is pivotably connected with the proximal side end link member, and a connecting end axis of the intermediate link member, which is pivotably connected with the distal side end link member cooperate with each other to form an angle γ therebetween, and connecting end axes of the intermediate link member, which are pivotably connected with the proximal end side and distal side end link members, and connecting end axes of the proximal end side link hub and the distal end side link hub, which are pivotably connected with the proximal end side link member and the distal end side link member, respectively, coo

Assignees

• Nishio Yukihiro
• Isobe Hiroshi
• Yamada Hiroyuki
• Ntn Toyo Bearing Co Ltd

Inventors

• Nishio Yukihiro
• Isobe Hiroshi
• Yamada Hiroyuki

Classifications

• Y10S901/02

  Arm motion controller · CPC title

• B25J9/1607 Primary

  Calculation of inertia, jacobian matrixes and inverses · CPC title

• G05B19/4103

  Digital interpolation · CPC title

• B25J9/1664

  characterised by motion, path, trajectory planning · CPC title

• G05B2219/40267

  Parallel manipulator, end effector connected to at least two independent links · CPC title