KR-102963031-B1 - TORQUE SENSOR WITH HIGH TORSIONAL STIFFNESS

KR102963031B1KR 102963031 B1KR102963031 B1KR 102963031B1KR-102963031-B1

Abstract

The present invention relates to a high-rigidity torque sensor, characterized by comprising: a hub forming an inner ring; a rim forming an outer ring spaced radially outward from the hub; a sensor plate forming the bottom of the spaced-out space by closing the spaced-out space between the hub and the rim on one side in the direction of the rotation axis of the hub and the rim; a plurality of spokes connecting the hub and the rim in a mutually spaced circumferential direction within the spaced-out space; and a plurality of strain sensors attached to the sensor plate to measure the strain of the sensor plate. Through this, the strain sensors are not attached to the spokes but are attached to the sensor plate between the hub and the rim to measure the strain of the sensor plate, thereby enabling accurate measurement of the strain.

Inventors

김서현
송재복

Assignees

(주)코라스로보틱스

Dates

Publication Date: 20260511
Application Date: 20240621

Claims (11)

In high-rigidity torque sensors, A hub forming an inner ring; A rim that forms an outer ring spaced radially outward from the above hub; A sensor plate that closes the gap between the hub and the rim on one side in the direction of the rotation axis of the hub and the rim to form the bottom of the gap; A plurality of spokes connecting the hub and the rim in a mutually spaced state along the circumferential direction in the spaced-apart space; A high-rigidity torque sensor characterized by including a plurality of strain sensors attached to the sensor plate to measure the strain of the sensor plate.
In paragraph 1, A high-rigidity torque sensor characterized in that a plurality of strain sensors are attached to the sensor plate in a mutually spaced manner along the circumferential direction, wherein at least one is attached to the sensor plate such that it is positioned between a pair of mutually adjacent spokes.
In paragraph 1, A high-rigidity torque sensor characterized in that each of the above-mentioned deformation sensors is attached to the outer or inner surface of the sensor plate.
In paragraph 1, A high-rigidity torque sensor characterized by a plurality of the above-mentioned strain sensors being attached to the sensor plate in a spaced-apart manner along the circumferential direction to form a Wheatstone bridge.
In paragraph 4, A high-rigidity torque sensor characterized by eight strain sensors arranged in pairs adjacent to each other, and four pairs of strain sensors arranged at equal intervals along the circumferential direction.
In paragraph 5, A plurality of the above spokes are positioned at equal intervals along the circumferential direction; A high-rigidity torque sensor characterized by a pair of mutually adjacent strain sensors being attached to the sensor plate so as to be positioned between a pair of mutually adjacent spokes.
In paragraph 1, A high-rigidity torque sensor characterized by having a plurality of through holes formed through the plate surface in the sensor plate.
In paragraph 1, It further includes an attachment plate that extends radially inward from the sensor plate and extends radially inward from the hub; A high-rigidity torque sensor characterized by a link of a reducer or robot being fastened to the hub to apply torque so as to contact the outer surface of the attachment plate.
In paragraph 1, A high-rigidity torque sensor characterized in that the hub, the rim, and the sensor plate are formed integrally.
In paragraph 1, A high-rigidity torque sensor characterized in that the hub, the rim, a plurality of the spokes, and the sensor plate are formed integrally.
In paragraph 1, A high-rigidity torque sensor characterized in that the thickness of the spokes in the direction of the rotational axis of the rim and the hub is thicker than the thickness of the sensor plate.

Description

High Torsional Stiffness Torque Sensor The present invention relates to a high-rigidity torque sensor, and more specifically, to a high-rigidity torque sensor capable of measuring the torque of a joint requiring high rigidity, such as a multi-joint robot. As the demand for assembly, transportation, and production using robots increases, there is a demand for robots that can collaborate with humans safely and allow non-experts to easily direct tasks. To achieve this, a hand guiding function is required that can detect collisions between humans and robots, and allows a human to directly direct tasks by grasping and moving the robot's end. In order to implement these functions, it is necessary to measure the torque that each joint of the robot applies to the link, and generally, torque sensors have been used to measure the torque that the joint applies to the link. Generally, torque sensors have a disc or cylindrical hub-spoke structure for effective deformation and accurate torque measurement. As an example, Korean Registered Patent No. 1335432 discloses a force-torque sensor having a hub-spoke structure. A torque sensor with a hub-spoke structure takes on a complex shape to maximize the deformation of the spokes to which strain gauges, which are deformation sensors, are installed. Here, since the spokes to which deformation must be maximized support the entire load, there is a limit to the torsional stiffness. To look at it more specifically, robot joints generally have a structure in which a motor, a reduction gear, and a torque sensor are connected in series. That is, the torque generated by the motor is amplified by the reduction gear to rotate the link, and a torque sensor is installed between the reduction gear and the link to measure the torque transmitted to the link. Since both the reduction gear and the torque sensor are rotational elastic bodies, torsional deformation occurs when torque is applied to them. In this case, the torque is determined by the product of the torsional deformation and the torsional stiffness. If the torsional stiffness of a torque sensor is small, large torsional deformation occurs even for the same torque, allowing for accurate torque measurement; therefore, most torque sensors are designed with low torsional stiffness. However, the low torsional stiffness of the torque sensor results in low torsional stiffness of the robot joint itself. This acts as a factor that reduces the torsional stiffness of the entire robot, which is composed of multiple joints, causing problems such as reduced precision and vibration. Therefore, torque sensors used in robots must be designed differently from general torque sensors. In other words, while general torque sensors are designed with low torsional stiffness for accurate torque measurement, it is desirable to design robot torque sensors to have as high a torsional stiffness as possible to ensure the robot's overall rigidity while still enabling accurate torque measurement. FIG. 1 is a perspective view of a high-rigidity torque sensor according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view of a high-rigidity torque sensor according to an embodiment of the present invention, and FIGS. 3 and 4 are perspective views of a sensor body of a high-rigidity torque sensor according to an embodiment of the present invention, and FIG. 5 is a drawing showing a cross-section along the line V-V of FIG. 3, and FIG. 6 is a drawing for explaining the arrangement of strain sensors and the Wheatstone bridge structure of a high-rigidity torque sensor according to an embodiment of the present invention, and FIG. 7 is a diagram showing an example in which the structure of a high-rigidity torque sensor according to an embodiment of the present invention is implemented as a spring model, and FIGS. 8 and 9 are drawings showing the simulation results of a high-strength torque sensor according to an embodiment of the present invention. The present invention is capable of various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the invention to specific embodiments, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention. The terms used in this application are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations the