Medical support arm device and medical system
There is provided a medical support arm device including a brake provided in at least one joint of a plurality of joints that define a deployment configuration of a multi-joint arm, and configured to release a rotation shaft of the at least one joint when electricity is supplied to the multi-joint arm and lock the rotation shaft when electricity is not supplied to the multi-joint arm. When electricity is not supplied the brake is configured to exert a brake force that supports a weight of the multi-joint arm to maintain the deployment configuration of the multi-joint arm, but also permits rotation of the rotation shaft by an external manually applied force equal to or larger than a predetermined value.
1. A medical system comprising:
a multi-joint arm including a plurality of joints;
a medical observation device including imaging circuitry and provided at a distal end of the multi joint arm to oppose a surgical site of a patient; and
power supply control circuitry configured to control a driving of an electric power supply to the multi joint arm and the imaging circuitry, the power supply control circuitry is configured to remove a supply of electricity from the electric power supply to the multi-joint arm, and preferentially supply electric power to the imaging circuitry, when an interruption of electrical power is experienced,
wherein at least one of the plurality of joints is provided with a brake configured to release a rotation shaft of the at least one joint when electricity is supplied and to lock the rotation shaft when electricity is not supplied, and
the brake is configured to support a weight of the multi joint arm to maintain a deployment configuration of the multi joint arm when electricity is not supplied, and apply a brake force that allows rotation of the rotation shaft by an external force equal to or larger than a predetermined value.
2. The medical system according to claim 1 , wherein
the medical observation device includes observation optics aligned to provide an optical path through the observation optics, to the surgical site.
3. The medical system according to claim 1 , wherein:
the brake force is equal to or greater than a supporting force to maintain the deployment configuration of the multi joint arm even when a maximum stress caused by a weight of the multi joint arm is exerted on at least one of the joints.
4. The medical system according to claim 1 , wherein
the brake force is equal to or greater than a supporting force to maintain the deployment configuration of the multi joint arm even when a maximum stress caused by a weight of the multi joint arm is exerted on at least one of the plurality of joints.
5. The medical system according to claim 1 , wherein
the brake force has at least a supporting force to maintain the deployment configuration of the multi joint arm even when the multi joint arm is fully stretched out horizontally.
6. The medical system according to claim 1 , wherein
the external applied force is a manual force cause by a user.
7. The medical system according to claim 1 , wherein
the multi joint arm is a power-assisted multi joint arm.
8. The medical system according to claim 4 , wherein
the brake force is controllably adjusted to correspond with a change in torque on the at least one of the joints depending on the deployment configuration of the multi joint arm.
9. The medical system according to claim 1 , wherein
a value of the brake force varies depending on a position at which the brake is provided in the multi joint arm.
10. The medical system according to claim 9 , wherein
the value of the brake force is smaller, as the brake is positioned closer to a distal end of the multi-joint arm.
11. The medical system according to claim 1 , wherein
the brake is provided only in a joint that defines a deployment configuration of a distal end device provided at a distal end of the multi joint arm.
12. The medical system according to claim 1 , wherein the brake includes:
an armature configured to be movable in a direction of the rotation shaft by a magnetic force generated by supplying electricity to a coil and returned by a restoring force of a spring;
a disk configured to rotate with the rotation shaft; and
a plate disposed opposite to the armature with the disk disposed therebetween, wherein
the rotation shaft is unlocked by a movement of the armature so as to create predetermined gaps between the armature, the disk, and the plate, the predetermined gaps being generated by the magnetic force, and
the rotation shaft being locked by a movement of the armature so as to press the disk to the plate by the restoring force of the spring, when electricity is not supplied.
13. The medical system according to claim 12 , wherein
the brake is controllably adjusted by setting at least one of a contact area between the disk and the plate, a static friction coefficient of contacting surfaces of the disk and the plate, and the restoring force of the spring.
14. The medical system according to claim 1 , wherein the brake includes:
a disk configured to rotate with the rotation shaft; and
a cylinder connected to a plate disposed opposite to the disk, and configured to be moved in a direction of the rotation shaft by hydraulic pressure and returned by a restoring force of a spring, wherein
the rotation shaft is unlocked by a movement of the cylinder so as to create a predetermined gap between the disk and the plate by the hydraulic pressure, when electricity is supplied, and
the rotation shaft is locked by a movement of the cylinder so as to press the plate to the disk by the restoring force of the spring, when electricity is not supplied.
15. The medical system according to claim 14 , wherein
the brake is controllably adjusted by setting at least one of a contact area between the disk and the plate, a static friction coefficient of contacting surfaces of the disk and the plate, and the restoring force of the spring.
16. The medical system according to claim 1 , wherein the brake includes:
a disk configured to rotate with the rotation shaft;
a yoke disposed opposite the disk in a direction of the rotation shaft and including a coil in an inner portion;
a permanent magnet disposed on a surface of the disk opposite the yoke member; and
a magnetic fluid disposed between the yoke and the permanent magnet, and configured to solidify to a solidified magnetic material according to an intensity of an applied magnetic field, wherein at least partial solidification of the magnetic material is experienced, and the rotation shaft is unlocked, by generating a magnetic field from the coil so as to cancel a magnetic field of the permanent magnet, by supplying electricity to the coil, when electricity is supplied, and
the yoke member and the disk are connected by the solidified magnetic material, and the rotation shaft is locked, by solidifying the magnetic fluid by the magnetic field from the permanent magnet, when electricity is not supplied.
17. The medical system according to claim 16 , wherein
the brake is controllably adjusted by setting at least one of a material of the magnetic fluid, a contact area between the solidified magnetic material and the yoke, a contact area between the solidified magnetic material and the permanent magnet, and a magnetic force of the permanent magnet.
18. A medical support arm device comprising:
a brake provided in at least one joint of a plurality of joints that define a deployment configuration of a multi joint arm, and configured to release a rotation shaft of the at least one joint when electricity is supplied to the multi joint arm and lock the rotation shaft when electricity is not supplied to the multi joint arm, wherein
when electricity is not supplied to the multi joint arm, the brake is configured to exert a brake force that supports a weight of the multi-joint arm to maintain the deployment configuration of the multi-joint arm, but also permits rotation of the rotation shaft by an external manually applied force equal to or larger than a predetermined value,
the medical support arm device is an observation device that includes imaging circuitry; and
power supply control circuitry configured to control a driving of an electric power supply to the multi joint arm and the imaging circuitry, the power supply control circuitry is configured to remove a supply of electricity from the electric power supply to the multi-joint arm, and preferentially supply electric power to the imaging circuitry, when an interruption of electrical power is experienced.
19. The medical support arm device according to claim 18 , wherein
the brake force is equal to or greater than a supporting force to maintain the deployment configuration of the multi joint arm even when a maximum stress caused by a weight of the multi joint arm is exerted on at least one of the plurality of joints.
20. The medical support arm device according to claim 18 , wherein
the brake force has at least a supporting force to maintain the deployment configuration of the multi joint arm even when the multi joint arm is fully stretched out horizontally.