Joint mechanism, method for controlling the same, multi-arm device, and robot

1. A joint mechanism ( 100 ), comprising:

a base ( 4 ) having a first and a second pivot shaft ( 41 );

a swinging arm ( 1 ) which is mounted on the pivot shaft ( 41 ) at a first end ( 11 ) thereof;

a first driving member ( 2 ) and a second driving member ( 3 ), which are each mounted on one of the first and the second pivot shaft ( 41 ) for receiving a driving force from a driving source, wherein the first driving member ( 2 ) and the second driving member ( 3 ) interact with the swinging arm ( 1 ) through magnetorheological fluid, respectively; and

a first electromagnetic component ( 22 ) and a second electromagnetic component ( 23 ), which are configured to change phase state of the magnetorheological fluid, so that the first driving member ( 2 ) and the second driving member ( 3 ) can selectively drive the swinging arm ( 1 ) to rotate along a first direction or a second direction, wherein the first direction is opposite to the second direction,

wherein the first driving member ( 2 ) and the second driving member ( 3 ) define, together with the swinging arm ( 1 ), a closed, first liquid cavity ( 21 ) and a closed, second liquid cavity ( 31 ) respectively, which are both filled with the magnetorheological fluid,

and further wherein the first end ( 11 ) of the swinging arm ( 1 ) is formed as a sleeve, which is divided into two recesses ( 13 , 14 ) through a partition wall ( 12 ) extending along a radial direction, and

wherein open ends of said two recesses ( 13 , 14 ) are closed by the first driving member ( 2 ) and the second driving member ( 3 ) respectively, so as to form the first liquid cavity ( 21 ) and the second liquid cavity ( 31 ).

2. The joint mechanism according to claim 1 , wherein the first driving member ( 2 ) and the second driving member ( 3 ) are each formed as a hollow shaft having an open end and a closed end,

the open ends of the first driving member ( 2 ) and the second driving member ( 3 ) are configured so that the pivot shaft ( 41 ) can be mounted thereon, and the closed ends thereof extend into the recesses ( 13 , 14 ) respectively, and

each hollow shaft is provided on an outer periphery thereof with an annular shoulder ( 25 , 35 ), which is sealingly connected with the open end of a respective recess ( 13 , 14 ) through a bearing ( 26 , 36 ), for closure of the first liquid cavity ( 21 ) or the second liquid cavity ( 31 ).

3. The joint mechanism according to claim 2 , wherein the first electromagnetic component ( 22 ) and the second electromagnetic component ( 23 ) are configured as annular members, which are arranged in the first liquid cavity ( 21 ) and the second liquid cavity ( 31 ), respectively, and sleeved on the closed ends of the first driving member ( 2 ) and the second driving member ( 3 ), respectively.

4. The joint mechanism according to claim 2 , wherein portions of the first driving member ( 2 ) and the second driving member ( 3 ) extending into the recesses are made of soft magnetic material.

5. The joint mechanism according to claim 1 , wherein the first electromagnetic component ( 22 ) and the second electromagnetic component ( 32 ) are arranged at a side of the first liquid cavity ( 21 ) and the second liquid cavity ( 31 ), respectively.

6. The joint mechanism according to claim 1 , wherein the driving source drives the first driving member ( 2 ) and the second driving member ( 3 ) to rotate in the first direction and the second direction respectively through a transmission mechanism, which is selected from a group consisting of a pulley, a gear, a sprocket and a belt.

7. The joint mechanism according to claim 6 , wherein the driving source drives the first driving member ( 2 ) through a first belt and a first pulley, and drives the second driving member ( 3 ) through a second belt and a second pulley, and

wherein the first belt adopts one of a cross-belt drive mode and an open-belt drive mode, while the second belt adopts the other of the cross-belt drive mode and the open-belt drive mode.

8. A multi-arm device ( 20 ), comprising:

a first joint mechanism according to claim 1 ; and

a second joint mechanism according to claim 1 , which is arranged at a second end ( 19 ) of the swinging arm ( 1 ) of the first joint mechanism,

wherein the base of the second joint mechanism is formed by the second end ( 19 ) of the swinging arm ( 1 ) of the first joint mechanism, and the driving source of the second joint mechanism is formed by the first driving member ( 2 ) and the second driving member ( 3 ) of the first joint mechanism.

9. A method of controlling the joint mechanism according to claim 1 , comprising a step of:

applying current to the first electromagnetic component ( 22 ) and/or the second electromagnetic component ( 23 ) to change the phase state of magnetorheological fluid, so that at least one of the first driving member ( 2 ) and the second driving member ( 3 ) can selectively drive the swinging arm ( 1 ) to rotate along the first direction or the second direction.

10. The method according to claim 9 , wherein the method includes any one or more of operation modes as follows:

a first operation mode, in which only a first current is applied to the first electromagnetic component ( 22 ), so that the magnetorheological fluid in the first liquid cavity changes its phase state, resulting in that the first driving member ( 2 ) can drive the swinging arm ( 1 ) to rotate in the first direction;

a second operation mode, in which only a second current is applied to the second electromagnetic component ( 32 ), so that the magnetorheological fluid in the second liquid cavity changes its phase state, resulting in that the second driving member ( 3 ) can drive the swinging arm ( 1 ) to rotate in the second direction;

a third operation mode, in which a third current and a fourth current are continuously applied to the first electromagnetic component ( 22 ) and the second electromagnetic component ( 32 ), respectively, so that the magnetorheological fluids in the first liquid cavity ( 21 ) and the second liquid cavity ( 31 ) both change their phase states, and a driving force exerted by the first driving member ( 2 ) on the swinging arm ( 1 ) is equal to that exerted by the second driving member ( 3 ) on the swinging arm ( 1 ), resulting in the swinging arm ( 1 ) being at a natural stationary state;

a fourth operation mode, in which a fifth current and a sixth current are continuously applied to the first electromagnetic component ( 22 ) and/or the second electromagnetic component ( 32 ), respectively, so that the magnetorheological fluid in the first liquid cavity ( 21 ) and/or the second liquid cavity ( 31 ) changes its phase states, and a driving force exerted by the first driving member ( 2 ) and/or the second driving member ( 3 ) on the swinging arm ( 1 ) counteracts to a gravity of the swinging arm ( 1 ), resulting in the swinging arm ( 1 ) being at a stationary state, the fifth current and the sixth current being pulse current; and

a fifth operation mode, in which a seventh current and an eighth current are alternately applied to the first electromagnetic component ( 22 ) and the second electromagnetic component ( 32 ), so that the magnetorheological fluids in the first liquid cavity ( 21 ) and the second liquid cavity ( 31 ) change their phase states in an alternate manner, and the first driving member ( 2 ) and the second driving member ( 3 ) drive the swinging arm ( 1 ) in an alternate manner, thus generating a reciprocating swing movement of the swinging arm ( 1 ).