CN110576455B - Modularized collision detection and protection device for multi-degree-of-freedom image robot - Google Patents

Abstract

The invention discloses a modularized collision detection and protection device for a multi-degree-of-freedom image robot, which comprises the following components: the device comprises a collision detection outer plate, a collision detection module, a robot controller, a direct current power supply and a solid state relay. The collision detection module consists of two detection layers and one buffer layer. When the collision detection outer plate contacts with an obstacle and generates a force, the detection outer plate enables the first layer of self-locking switch to act and transmits the information to the robot controller, and the robot actively stops moving; when the bottom plate of the first layer self-locking switch enables the second layer self-locking switch to act under the action of the detection outer plate, the solid state relay acts, the power supply of the robot is cut off, and the robot passively stops moving. The invention can protect the image robot when the image robot contacts with the obstacle and the interaction force between the image robot and the obstacle is small, has high sensitivity, avoids the damage of equipment and other objects on site, has simple and reliable structure, is convenient to install and use and has low cost.

Description

Modular collision detection and protection device for multi-degree-of-freedom imaging robots

Technical Field

The present invention belongs to the technical field of medical devices, and in particular relates to a collision detection and protection device applied to a multi-degree-of-freedom imaging robot.

Background technique

The scanning trajectory of the multi-degree-of-freedom imaging robot is flexible, and a personalized scanning imaging trajectory can be set according to the imaging task. It has good application prospects in intraoperative precise navigation, adaptive radiotherapy, and early screening and diagnosis of tumors. The imaging trajectory of the task-driven multi-degree-of-freedom imaging robot is complex, and the robot's collision detection and protection issues must be properly handled, especially in the medical application of multi-degree-of-freedom imaging robots. Once the equipment fails or an accident occurs on site, the imaging robot may collide with surrounding objects, which will not only affect the normal operation of the system, but also damage the robot in serious cases, and even cause harm to on-site personnel.

Summary of the invention

In view of the potential safety hazards and other shortcomings of multi-degree-of-freedom imaging robots, the present invention designs a modular collision detection and protection device for multi-degree-of-freedom imaging robots based on the characteristics of the multi-degree-of-freedom imaging robot's own movement. The present invention can perform protective actions when the imaging robot comes into contact with an obstacle and the interaction force between the two is small. It has high sensitivity and can avoid damage to the equipment and other objects on site. It has a simple and reliable structure, is easy to install and use, and has low cost.

The present invention is implemented through the following technical solutions: A modular collision detection and protection device for a multi-degree-of-freedom imaging robot, comprising: at least one collision detection outer plate, at least two collision detection modules, a robot controller, a DC power supply and a solid-state relay; wherein the collision detection outer plate and the collision detection module are used to detect the collision between the robot and an obstacle, and the robot controller and the solid-state relay are used to generate a protection operation;

The collision detection module has a three-layer structure, the top layer includes a first bottom plate and at least one self-locking switch installed on the first bottom plate; the middle layer includes a second bottom plate and at least one self-locking switch installed on the second bottom plate; the bottom layer includes a third bottom plate; the first bottom plate, the second bottom plate and the third bottom plate are connected in sequence by springs;

Each collision detection outer panel is supported by at least two collision detection modules;

The self-locking switches on the first bottom plates of all collision detection modules are connected in series and connected to the robot controller to form a first loop;

The self-locking switches on the second bottom plate of all collision detection modules are connected in series and then connected to the control end of the solid-state relay through an auxiliary DC power supply to form a second circuit;

The device has two levels of collision detection and protection functions:

When no collision occurs, both the first circuit and the second circuit are passages;

When the collision detection outer plate comes into contact with an obstacle, causing at least one self-locking switch on the top layer to be actuated, the first circuit is disconnected, and a disconnection signal is transmitted to the robot controller, which issues a command to cause the robot to immediately and actively stop moving;

When the first bottom plate of the top layer continues to move under the action of the collision detection outer plate, causing at least one self-locking switch of the middle layer to be actuated, the second circuit is disconnected, the solid-state relay is actuated, the power supply of the robot is cut off, and the robot stops moving passively;

If the robot stops moving passively, it takes a very short period of time from the action of the solid-state relay to the complete stop of the robot. During this period, the tube and detector at the end of the imaging robot will still produce a certain displacement; the spring between the second base plate and the third base plate, in addition to the connection and support functions, also has a buffering function to protect the imaging robot and collision objects.

Furthermore, the robot controller records the current position and posture of the robot every T ₀ time. When programming the robot trajectory, the time required to complete each motion control instruction is defined. Therefore, the motion control instruction when the collision occurs can be known according to the time when the collision occurs. The robot posture recorded when the last collision did not occur is used as the target point, the posture of the robot actively stopping the movement is used as the starting point, and the motion control instruction when the collision occurs is used as the return control instruction, so that the robot returns to the place where no collision occurs along the original trajectory and then stops moving.

Furthermore, four self-locking switches are arranged on the top and middle layers of the collision detection module, each self-locking switch is composed of two single-pole double-throw switches, and the eight single-pole double-throw switches of the four self-locking switches on each layer are connected in series in sequence; when no collision occurs, the eight single-pole double-throw switches on each layer form a current conduction path, and after a collision occurs, when at least one self-locking switch is pressed, the current path is disconnected.

Furthermore, the collision detection outer plate is 3D printed according to the appearance shape of the robot where the collision detection module is installed. Several collision detection outer plates are pieced together into the shape of the robot's appearance and covered on the surface of the robot. The collision detection outer plate is fixed on the self-locking switch on the top layer of the collision detection module. The collision detection module is installed between the collision detection outer plate and the imaging robot body. According to the specific shape of the collision detection outer plate, only a few collision detection modules need to be arranged along its edge, which greatly reduces the number and cost of sensors.

Furthermore, at least three first springs are installed between the first bottom plate and the second bottom plate of the collision detection module, and at least three second springs are installed between the second bottom plate and the third bottom plate. The first springs play two roles of fixing and supporting, and the second springs play three roles of fixing, supporting and buffering. When the collision detection outer plate and the self-locking switch of the first layer act with force, the first bottom plate produces a very small displacement under the support of the springs between the first bottom plate and the second bottom plate, and _K2 and _K3 are required to be greater than _K1 to ensure the sensitivity of collision detection. When the second layer self-locking switch is actuated, the second bottom plate produces a very small displacement under the support of the springs between the second bottom plate and the third bottom plate, and _K3 is required to be greater than _K2 . Among them, _K1 is the equivalent stiffness coefficient of all the internal springs of the self-locking switches of the first layer, _K2 is the equivalent stiffness coefficient of all the springs between the first bottom plate and the second bottom plate, and _K3 is the equivalent stiffness coefficient of all the springs between the second bottom plate and the third bottom plate.

Furthermore, four springs are installed between the first bottom plate and the second bottom plate, and five springs are installed between the second bottom plate and the third bottom plate.

The beneficial effects of the present invention are as follows: the collision detection outer plate of the present invention is 3D printed according to the appearance of the robot where the collision detection module is installed. According to the specific shape of the collision detection outer plate, only a few collision detection modules need to be arranged along its edge, which greatly reduces the number and cost of sensors; the collision detection module is composed of two detection layers and one buffer layer, so that the device has two-level collision detection and protection functions, and the buffer layer leaves enough time for the robot to stop completely. The present invention can perform protective actions when the image robot comes into contact with an obstacle and the interaction force between the two is small. It has high sensitivity, avoids damage to equipment and other objects on site, has a simple and reliable structure, is easy to install and use, and has low cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a multi-DOF imaging robot arm with a collision detection outer plate and a collision detection module installed;

FIG2 is a three-layer structure diagram of a collision detection module;

FIG3 is a general schematic diagram of the inventive device;

FIG4 is a flow chart of collision detection and protection of the inventive device;

FIG5 is an X-ray flat panel detector with a collision detection outer plate and a collision detection module installed;

In the figure: 1. Collision detection outer panel; 2. Collision detection module; 3. Multi-DOF imaging robot arm; 4. First-layer self-locking switch; 5. First bottom plate; 6. Second-layer self-locking switch; 7. First spring; 8. Second bottom plate; 9. Second spring; 10. Third bottom plate; 11. Wire for connecting the first-layer self-locking switch to the first circuit; 12. Wire for connecting the second-layer self-locking switch to the second circuit; 13. Robot controller; 14. DC power supply; 15. Solid-state relay; 16. X-ray flat-panel detector; 17. Fixing and supporting structure of the flat-panel detector.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

Figure 1 shows a multi-DOF imaging robot arm 3 with a collision detection outer plate 1 and a collision detection module 2 installed. When the collision detection outer plate 1 contacts an obstacle, due to the support of the first spring 7 between the first bottom plate 5 and the second bottom plate 8 in the collision detection module 2, the first layer self-locking switch 4 of the collision detection module 2 is actuated, and the first circuit A is disconnected.

FIG2 shows a collision detection module. The collision detection module 2 has a three-layer structure, the first layer is four self-locking switches, the second layer is four self-locking switches and four first springs 7 , and the third layer is five second springs 9 .

First layer: Each self-locking switch is composed of two single-pole double-throw switches, and the eight single-pole double-throw switches of the four self-locking switches are connected in series in sequence. When there is no collision, the eight single-pole double-throw switches form a current conduction path. After the collision occurs, at least one self-locking switch is pressed, and the current path is disconnected.

Second layer: The connection mode and working principle of the four second-layer self-locking switches 6 are the same as those of the first layer, and the four first springs 7 have two functions: fixing and supporting. When the collision detection outer plate 1 and the four self-locking switches of the first layer act with force, the first bottom plate 5 produces a very small displacement under the support of the four springs between the first bottom plate 5 and the second bottom plate 8. It is required that K ₂ and K ₃ are both greater than K ₁ to ensure the sensitivity of the collision detection, where K ₁ is the equivalent spring coefficient of all the internal springs of the self-locking switches of the first layer, K ₂ is the equivalent spring coefficient of all the springs between the first bottom plate and the second bottom plate, and K ₃ is the equivalent spring coefficient of all the springs between the second bottom plate and the third bottom plate.

The third layer: The second spring 9 between the second bottom plate 8 and the detection module installation bottom plate, i.e., the third bottom plate 10, has three functions: connection, support and buffer. When the second layer self-locking switch 6 is actuated, the second bottom plate 8 is required to produce a small displacement under the support of the spring between the second bottom plate 8 and the third bottom plate 10. Therefore, K ₃ is required to be greater than K ₂ .

The self-locking switches on the first bottom plate 5 of all collision detection modules 2 are connected in series and connected to the I/O board of the robot controller 13 to form a first loop A;

After the self-locking switches on the second base plate 8 of all collision detection modules 2 are connected in series, they are connected to the control end of the solid-state relay 15 through the auxiliary DC power supply 14 to form a second loop B. The DC power supply 14 supplies power to the control end of the solid-state relay 15 to ensure that the robot's drive control system can be reliably powered when the second loop B is working normally.

The device has two levels of collision detection and protection functions:

When no collision occurs, both the first circuit and the second circuit are passages;

When the collision detection outer plate comes into contact with an obstacle, causing at least one self-locking switch on the top layer to be actuated, the first circuit is disconnected, and a disconnection signal is transmitted to the robot controller, which issues a command to cause the robot to immediately and actively stop moving;

When the first bottom plate of the top layer continues to move under the action of the collision detection outer plate, causing at least one self-locking switch of the middle layer to be actuated, the second circuit is disconnected, the solid-state relay is actuated, the power supply of the robot is cut off, and the robot stops moving passively;

If the robot stops moving passively, it takes a very short period of time from the action of the solid-state relay to the complete stop of the robot. During this period, the tube and detector at the end of the imaging robot will still produce a certain displacement; the spring between the second base plate and the third base plate, in addition to the connection and support functions, also has a buffering function to protect the imaging robot and collision objects.

The following measures can also be taken to process the first circuit breaking signal: the robot controller records the current position and posture of the robot every _T0 time. When programming the robot trajectory, the time required to complete each motion control instruction is defined. Therefore, the motion control instruction when the collision occurs can be known according to the time when the collision occurs. The robot position recorded when the last collision did not occur is used as the target point, the position where the robot actively stops moving is used as the starting point, and the motion control instruction when the collision occurs is used as the return control instruction, so that the robot returns to the place where no collision occurs along the original trajectory and then stops moving.

Figure 4 shows a working flow chart of a modular collision detection and protection device for a multi-DOF imaging robot. After the robot is powered on and receives the command to start running, it runs according to the trajectory set by the program and records the actual running trajectory, and collects images at the specified position. At the same time, the robot controller monitors the on-off status of the first circuit. When the first circuit is detected to be broken, the robot controller issues a command to make the robot return to the original trajectory to a place where no collision occurs and then actively stop moving.

If the solid-state relay control terminal does not detect the disconnection signal of the second circuit after the first circuit is disconnected, it means that the robot has completely stopped moving before the second-layer self-locking switch is activated. In this case, the power supply of the robot can be manually turned off, and then the staff can conduct on-site investigation of the cause of the collision.

If the second-layer self-locking switch is activated before the robot stops moving completely, the control circuit of the solid-state relay, i.e. the second circuit, will cut off the power supply of the robot after the circuit is broken, and the robot will stop moving passively, which is equivalent to an emergency stop of the robot.

FIG5 is an X-ray flat panel detector with a collision detection outer plate and a collision detection module installed. The collision detection module 2 and the collision detection outer plate 1 are installed on the three sides of the X-ray flat panel detector 16 where it is possible to collide with obstacles, and the X-ray flat panel detector 16 is fixed on the fixing and supporting structure 17 of the flat panel detector. The flat panel detector is an important component of the imaging robot, located at the end of the imaging robot, and has a large range of motion. Especially in the task-driven impact detection method, the running trajectory of the detector is relatively complex. Therefore, collision detection outer plates are set on the three outer sides of the detector. Since the imaging robot runs relatively slowly during the imaging process, a collision detection module based on a self-locking switch with two-stage collision detection and protection functions combined with a collision detection outer plate can play a good protective role for the flat panel detector.

The above only provides a specific arrangement and use method of the collision detection module and the collision detection outer plate for the upper arm and the flat-panel detector of the imaging robot. The collision detection module and the collision detection outer plate of other components such as the X-ray tube on the imaging robot can also be designed and arranged by referring to the above method.

Although the exemplary implementation form is described by taking the arm of the multi-degree-of-freedom imaging robot and the X-ray flat panel detector as examples in the description of the specific implementation of the device, it should be pointed out that there are still a large number of variants available for other components of the multi-degree-of-freedom imaging robot. At the same time, the exemplary implementation form is only an example and should not be considered as any form of limitation on the protection scope, applicability and device structure according to the exemplary embodiment. More specifically, the above-mentioned specific implementation form is to provide guidance instructions for imaging robot professionals using an exemplary implementation form, and any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims (6)

1. A modular collision detection and protection device for a multi-degree-of-freedom imaging robot, characterized in that it comprises: at least one collision detection outer plate, at least two collision detection modules, a robot controller, a DC power supply and a solid-state relay; The collision detection module has a three-layer structure, the top layer includes a first bottom plate and at least one self-locking switch installed on the first bottom plate; the middle layer includes a second bottom plate and at least one self-locking switch installed on the second bottom plate; the bottom layer includes a third bottom plate; the first bottom plate, the second bottom plate and the third bottom plate are connected in sequence by springs; Each collision detection outer panel is supported by at least two collision detection modules; The self-locking switches on the first bottom plates of all collision detection modules are connected in series and connected to the robot controller to form a first loop; The self-locking switches on the second bottom plate of all collision detection modules are connected in series and then connected to the control end of the solid-state relay through an auxiliary DC power supply to form a second circuit; When no collision occurs, both the first circuit and the second circuit are passages; When the collision detection outer plate comes into contact with an obstacle, causing at least one self-locking switch on the top layer to be actuated, the first circuit is disconnected, and a disconnection signal is transmitted to the robot controller, which issues a command to cause the robot to immediately and actively stop moving; When the first bottom plate of the top layer continues to move under the action of the collision detection outer plate, causing at least one self-locking switch of the middle layer to be actuated, the second circuit is disconnected, the solid-state relay is actuated, the power supply of the robot is cut off, and the robot passively stops moving. 2. A modular collision detection and protection device for a multi-degree-of-freedom imaging robot according to claim 1, characterized in that the robot controller records the current posture of the robot every T ₀ time, and when programming the robot trajectory, defines the time required to complete each motion control instruction, and the motion control instruction when the collision occurs can be known according to the time when the collision occurs, and the robot posture recorded when the last collision did not occur is used as the target point, the posture of the robot actively stopping the movement is used as the starting point, and the motion control instruction when the collision occurs is used as the return control instruction, so that the robot returns to the place where no collision occurs along the original trajectory and then stops moving. 3. According to claim 1, a modular collision detection and protection device for a multi-degree-of-freedom imaging robot is characterized in that four self-locking switches are arranged on the top layer and the middle layer of the collision detection module, each self-locking switch is composed of two single-pole double-throw switches, and the eight single-pole double-throw switches of the four self-locking switches on each layer are connected in series in sequence; when no collision occurs, the eight single-pole double-throw switches on each layer form a current conduction path, and after a collision occurs, when at least one self-locking switch is pressed, the current path is disconnected. 4. A modular collision detection and protection device for a multi-degree-of-freedom imaging robot according to claim 1, characterized in that the collision detection outer plate is 3D printed according to the appearance shape of the robot where the collision detection module is installed, and is pieced together by several collision detection outer plates into the shape of the robot's appearance and covered on the surface of the robot. The collision detection outer plate is fixed on the self-locking switch on the top layer of the collision detection module, and the collision detection module is installed between the collision detection outer plate and the imaging robot body. 5. A modular collision detection and protection device for a multi-DOF imaging robot according to claim 1, characterized in that at least three first springs are installed between the first base plate and the second base plate of the collision detection module, and at least three second springs are installed between the second base plate and the third base plate, the first springs play two roles of fixing and supporting, and the second springs play three roles of fixing, supporting and buffering; when the collision detection outer plate and the self-locking switch of the first layer act with force, the first base plate generates a very small displacement under the support of the springs between the first base plate and the second base plate, and _K2 and _K3 are both required to be greater than _K1 ; when the second layer self-locking switch is actuated, the second base plate generates a very small displacement under the support of the springs between the second base plate and the third base plate, and _K3 is required to be greater than _K2 ; wherein, _K1 is the equivalent stiffness coefficient of all springs inside the self-locking switches of the first layer, _K2 is the equivalent stiffness coefficient of all springs between the first base plate and the second base plate, and _K3 is the equivalent stiffness coefficient of all springs between the second base plate and the third base plate. 6. A modular collision detection and protection device for a multi-degree-of-freedom imaging robot according to claim 1, characterized in that four springs are installed between the first base plate and the second base plate, and five springs are installed between the second base plate and the third base plate.