CN117428825A - Safety system for a mechanical appliance - Google Patents

Abstract

A safety system for a mechanical appliance. The mechanical device comprises a control system and a safety system. The safety system is coupled with the control system, monitors the operation of the mechanical appliance, and generates a first monitoring signal and a second monitoring signal according to a synchronization signal, wherein the first monitoring signal and the second monitoring signal are obtained by monitoring the mechanical appliance at the same monitoring time.

Description

Safety system for a mechanical appliance

Technical Field

The invention relates to a safety system, in particular to a safety system of a mechanical appliance, which improves the monitoring accuracy.

Background

A typical machine tool, such as a robot, utilizes a safety system to monitor whether the robot is operating in compliance with safety regulations, such as ISO 13849-1:2015category 2. Furthermore, the prior art generally integrates and designs the safety system and the control system as a single system, and uses the single control system to control the arm to perform tasks and to control the monitoring, operation or whether to activate the safety mechanism to limit the motion of the robot arm, such as the safety code IEC 61508-6:2010 1oo1. However, when the control system is abnormal, the integrated design cannot function after the safety system monitors the operation of the mechanical device, so that the safety requirement is not met, and the operation of the safety system also interferes with the data transmission performance of the control system.

Based on the above-mentioned problems, the present invention provides a safety system for a mechanical apparatus, so as to improve the data transmission performance of a control system and the accuracy of the safety system in monitoring the mechanical apparatus.

Disclosure of Invention

The invention aims to provide a safety system of a mechanical appliance, which monitors the mechanical appliance in a dual-channel architecture.

The invention aims to provide a safety system of a mechanical appliance, which utilizes a synchronous signal to control the correctness of data acquired by the safety system so as to correctly judge the motion state of the mechanical appliance.

The invention aims to provide a mechanical appliance, wherein a control system and a safety system of the mechanical appliance are mutually independent, so that the data transmission performance of the control system is improved.

To achieve the above object, the present invention provides a mechanical device comprising a control system and a safety system. The safety system is coupled with the control system, monitors the operation of the mechanical appliance, and generates a first monitoring signal and a second monitoring signal according to a synchronization signal, wherein the first monitoring signal and the second monitoring signal are obtained by monitoring the mechanical appliance at the same monitoring time.

The control system comprises a first temporary storage circuit and a second temporary storage circuit, wherein the first temporary storage circuit and the second temporary storage circuit respectively temporarily store first input data and second input data. The mechanical appliance comprises a communication control module which controls the control system to output the first input data or the second input data. The security system comprises a first monitoring module and a second monitoring module. The first monitoring module is coupled to the first temporary storage circuit through a communication interface, and the second monitoring module is coupled to the second temporary storage circuit to sequentially receive the first input data and the second input data. The first monitoring module and the second monitoring module respectively comprise a synchronous circuit, and the synchronous signal controls the synchronous circuit to trigger the first monitoring module and the second monitoring module to detect the state of the mechanical appliance at the same monitoring time so as to generate a first monitoring signal and a second monitoring signal. The safety system outputs first output data and second output data according to the first monitoring signal and the second monitoring signal.

Drawings

FIG. 1 is a schematic diagram of a robot and arm controller according to the present invention;

FIG. 2 is a circuit diagram of the control system and safety system of the joint module of the present invention;

FIG. 3 is a first circuit diagram of the control system and the safety system of the arm controller according to the present invention;

FIG. 4 is a second circuit diagram of the control system and the safety system of the arm controller according to the present invention;

FIG. 5 is a first circuit diagram of the control system and safety system of the present invention; a kind of electronic device with high-pressure air-conditioning system

FIG. 6 is a second circuit diagram of the control system and safety system of the present invention.

[ symbolic description ]

1. Mechanical arm

2. Joint module

21. Joint control system

22. Communication control module

23. Joint safety system

24. First monitoring module

25. Second monitoring module

26. Arm control system

27. Arm safety system

28. Synchronous circuit

29. Synchronous circuit

3. Pivot arm module

30. First temporary storage circuit

31. Second temporary storage circuit

32. Temporary storage circuit

33. Temporary storage circuit

4. Arm controller

41. First microprocessor, MCU1

42. Second microprocessor, MCU2

A _IN A input circuit

A _OUT A output circuit

B _IN B input circuit

B _OUT B output circuit

C _IN C input circuit

C _OUT C output circuit

E _IN E input circuit

E _OUT E output circuit

F _IN F input circuit

F _OUT F output circuit

DIN input data

DIN1 first input data

DIN2 second input data

DOUT output data

DOUT1 first output data

DOUT2 second output data

P1 communication interface

P2 communication interface

P3 communication interface

S1 first interrupt signal

S2 second interrupt signal

S3 third interrupt Signal

S4 fourth interrupt Signal

SYNC synchronization signal

Detailed Description

In order to achieve the above objects, the technical means and effects thereof adopted by the present invention are as follows, and the present invention is now illustrated by way of example with reference to the accompanying drawings.

Please refer to fig. 1, which is a schematic diagram of a robot and a manipulator controller according to the present invention. In an embodiment, the mechanical apparatus may be a robot arm 1, which includes a plurality of joint modules 2 and a plurality of shaft arm modules 3. The robot 1 is electrically connected to a robot controller 4. As shown, the joint modules 2 of the robot 1 are coupled to the robot controller 4. The arm controller 4 outputs an input data D _IN To the joint module 2, and the joint module 2 outputs an output data D _OUT To the arm controller 4. Wherein the arm controller 4 can output single input data D _IN To each joint module 2, or each joint module 2 receives a plurality of input data D _IN . Similarly, each joint module 2 can output single output data D _OUT To the arm controller 4, or to output a plurality of output data D _OUT To the arm controller 4. The input data D _IN And output data D _OUT The number of transmissions of (a) depends on the requirements of the robot 1 and the arm controller 4, such as single channel/dual channel safety monitoring or operation real-time monitoring.

Please refer to fig. 2, which is a circuit diagram of a control system and a safety system of the joint module of the present invention. The joint module 2 includes a control system and a safety system, and the control system and the safety system are disposed in the joint module 2, and may be referred to as a joint control system 21 and a joint safety system 23, which are given by way of illustration only, and not limitation of the applicable scope of the control system and the safety system. As shown, the joint module 2 is coupled to the arm controller 4, and in the embodiment of fig. 2, the circuit architecture is a dual-channel type, and a plurality of data are mutually transmitted. The arm controller 4 may include a first microprocessor 41 and a second microprocessor 42, wherein the first microprocessor 41 and the second microprocessor 42 respectively output a first input data D _IN1 And a second input data D _IN2 To the joint module 2. A first output data D outputted by the joint module 2 _OUT1 And a second output data D _OUT2 May be output by the joint control system 21 or the joint safety system 24.

In connection with the above, the joint control system 21 drives the motor to control the joint module 2 to move the robot arm 1. The joint safety system 23 is coupled to the joint control system 21, and the joint safety system 23 monitors the operation of the robot 1 to generate the first output data D _OUT1 And second output data D _OUT2 . Therefore, when the joint safety system 23 is not designed to control the operation of the joint module 2, the joint safety system 23 generates the first output data D _OUT1 And second output data D _OUT2 Is transmitted to the joint control system 21 and to the arm controller 4. Conversely, when the joint safety system 23 is designed to control the operation of the joint module 2, the existence of the mechanical device can be monitoredIn the case of a full doubt, the control joint module 2 stops the operation of the unsafe portion and transmits the relevant information (or data) to the arm controller 4, and the arm controller 4 determines the operation correction of the mechanical device. For example, when the joint safety system 23 detects that the operation voltage of the joint module 2 is insufficient, the mechanical device is controlled to reduce the operation speed in advance, and the first/second output data D is transmitted _OUT1-2 To the arm controller 4, the arm controller 4 then determines whether to stop the operation of the whole mechanical apparatus, display that maintenance is required, or continuously complete the subsequent tasks using the low-speed operation mode.

Furthermore, in the embodiment, the control system and the safety system of the joint module 2 are disposed independently, so that the control system can mainly control the operation of the joint module 2 to perform tasks, and the safety system mainly monitors and/or controls the safety operation of the joint module 2. Referring back to fig. 2, the joint module 2 includes a communication control module 22 that controls the data transmission between the joint control system 21 and the joint safety system 23, so that the data transmission between the joint control system 21 is not hindered by the data transmission between the joint safety system 23, i.e. the data transmission between the joint control system 21 can be performed when the joint safety system 23 is not performing the data transmission, and the data transmission performance of the joint control system 21 is improved, and vice versa. The communication control module 22 is coupled to the joint control system 21 and notifies the joint control system 21 to output the first input data D _IN1 Or a second input data D _IN2 And coupled to the joint safety system 23, the joint safety system 23 is informed to receive the first input data D _IN1 Or second input data D _IN2 . Similarly, when the joint security system 23 needs to transmit the first output data D via the communication control module 22 _OUT1 Or second output data D _OUT2 When the joint control system 21 is reached, the communication control module 22 can still control the data transmission time sequence, so as to avoid affecting the operation efficiency of the joint control system 21.

The machine comprises a synchronization signal SYNC which may be output by the arm controller 4 (e.g. MCU1 or MCU 2), the joint control system 21 or the joint safety system 23. For example, when the synchronization signal SYNC is output by the joint security system 23, the switch is turned offThe joint safety system 23 monitors the operation of the mechanical arm 1 according to the synchronization signal SYNC, and since the joint safety system 23 is a dual-channel circuit architecture, the joint safety system 23 monitors the operation of the mechanical arm 1 at the same monitoring time to obtain a first monitoring signal and a second monitoring signal. Wherein the first and second monitor signals can be a value detected as the first output data D _OUT1 And second output data D _OUT2 Such as the voltage value of the power supply voltage, the current value of the motor current, or the number of turns of the encoder. Alternatively, the first monitoring signal and the second monitoring signal are calculated by the security system 23 and then outputted as the first output data D _OUT1 And second output data D _OUT2 For example, a low voltage state, an overcurrent, or an operation speed which is inconsistent with the setting after the operation, and the like.

In addition, both logical and mathematical operations are options that can be designed. Signals, data, information, voltages or currents, etc. in the embodiments are various forms of description methods, which do not affect implementation of the embodiments. When the first monitoring signal and the second monitoring signal are generated by the joint module 2, they may be referred to as a first joint monitoring signal and a second joint monitoring signal.

Referring to fig. 2, the first monitoring module 24 or the second monitoring module 25 of the joint safety system 23 outputs the synchronization signal SYNC, for example, the first monitoring module 24 outputs the synchronization signal SYNC to the second monitoring module 25. In this way, the first monitoring module 24 notifies the second monitoring module 25 to synchronously monitor the operation state, the circuit state, the power supply state, or the like of the robot arm 1. Based on the synchronous monitoring of the first monitoring module 24 and the second monitoring module 25, the accuracy of the monitored value (data or signal) can be improved, namely, the accuracy of the safety system on the monitoring of the mechanical appliance is improved. If the monitoring is asynchronous, the first monitoring module 24 monitors the force application state of the mechanical arm 1 for 5 seconds before the mechanical arm 1, and the second monitoring module 25 monitors the force application state of the mechanical arm 1 for 5 seconds after the mechanical arm 1, and the force application state monitored by the difference of 5 seconds has a higher misjudgment probability for evaluating whether the mechanical arm 1 operates normally or abnormally. Furthermore, the synchronization signal SYNC is processed by a synchronization circuit provided in the joint safety system 23, for example, the first monitoring module 24 and the second monitoring module 25 are each provided with a synchronization circuit 28, 29, so as to generate and process the synchronization signal SYNC.

In other words, the safety system monitors the operation of the mechanical device and generates the first monitoring signal and the second monitoring signal according to the synchronization signal SYNC, wherein the first monitoring signal and the second monitoring signal are obtained by monitoring the mechanical device at the same monitoring time, so as to correctly determine the motion state of the mechanical device. The synchronization signal of the joint module 2 may be referred to as a joint synchronization signal. In addition, the dual-channel circuit architecture refers to a circuit architecture in which one channel is the first microprocessor 41, and related first input data D _IN1 Related first input data D _IN1 The communication control module 22 and the first monitoring module 24 of the communication control system, and the other channel is a second microprocessor 42, related to the second input data D _IN2 Control system of (c) and related second input data D _IN2 Is provided, and a second monitoring module 25. If one of the channels is abnormal and can not operate, the other channel can keep the joint modules 2 to the mechanical arm 1 to continue to operate normally, so that the delay of task execution is avoided.

Please refer to fig. 3, which is a first circuit diagram of the control system and the safety system of the arm controller of the present invention. The control system and the safety system can be applied to the arm controller 4 in addition to the joint module 2 of fig. 2. As shown, the control system and the safety system may be referred to as an arm control system 26 and an arm safety system 27, and the input data D of this embodiment _IN And output data D _OUT All of which are transmitted by the communication control module 22 and the arm control system 26 between the first microprocessor 41, the second microprocessor 42 and the arm safety system 27, wherein the input data D _IN And output data D _OUT May be a single-pen or multi-pen input data D _IN And output data D _OUT For example, input data D _IN Comprising first input data D _IN1 And second input data D _IN2 Output data D _OUT As well as the same. Furthermore, when the hand is in handThe arm safety system 27 monitors that the operating point of the robot arm 1 is not set or the movement error is too large, and transmits the monitored value (or the operation result) to the first microprocessor 41 or the second microprocessor 42, and further uses the monitored value (or the operation result) as the input data D of the joint module 2 _IN Which in turn triggers each articulation control system 21 to modify the drive to the motor. The relevant monitoring values (or calculation results) are transmitted to the joint control system 21 of the joint module 2, for example, by the first microprocessor 41, the second microprocessor 42, the arm control system 26, the communication control module 22 or the arm safety system 27 of the arm controller 4. Therefore, when both the joint module 2 and the arm controller 4 are designed with the control system and the safety system, if the joint module 2 reports the monitoring signal to the arm controller 4, the joint module 2 generates the output data D _OUT I.e. the input data D of the arm controller 4 _IN The safety system 23, for example the joint module 2 in fig. 2, generates first output data D _OUT1 And second output data D _OUT2 The first microprocessor 41 and the second microprocessor 42 of the arm controller 4 in fig. 3 are used as the first input data D of the arm controller 4 in fig. 32 _IN1 And second input data D _IN2 (i.e., first joint monitoring signal and a second joint monitoring signal).

In addition, the output data D generated by the arm controller 4 _OUT (i.e. first monitoring signal and second monitoring signal) as input data D of the joint module 2 _IN In this case, the first monitoring signal and the second monitoring signal may be referred to as a first arm monitoring signal and a second arm monitoring signal, and the synchronization signal may be referred to as an arm synchronization signal. Thus, the joint module 2 receives the input data D _IN The first arm monitoring signal or the second arm monitoring signal can be used for adjusting the driving of the motor. The remaining technical content of the embodiment of fig. 3 is similar to that of the embodiment of fig. 2 and will not be repeated here.

Please refer to fig. 4, which is a second circuit diagram of the control system and the safety system of the arm controller of the present invention. Unlike the embodiment of fig. 4 and the embodiment of fig. 3, the first monitoring module 24 and the second monitoring module 25 of the embodiment of fig. 4 are respectively coupled to the first microprocessor 41 and the second microprocessorA processor 42 for directly transmitting the first output data D _OUT1 And second output data D _OUT2 To the first microprocessor 41 and the second microprocessor 42. The remaining technical content of the fig. 4 embodiment is similar to that of the fig. 3 embodiment and will not be repeated here.

Please refer to fig. 5, which is a first circuit diagram of the control system and the safety system of the present invention. According to the example of the joint module 2, the joint control system 21, the first monitoring module 24 and the second monitoring module 25 all comprise temporary storage circuits. Because of the dual-channel architecture, the joint control system 21 includes a first register circuit 30 and a second register circuit 31, and the first monitor module 24 and the second monitor module 25 each include a single register circuit 32, 33. In addition, the communication control module 22 may be a single module independently as in the embodiment of fig. 2 to 4, or may be disposed in a distributed manner in the joint control system 21, the first monitoring module 24, and the second monitoring module 25 as in the embodiment of fig. 5. As shown, the communication control module 22 may include an a input circuit a _IN A output circuit A _OUT B input circuit B _IN B output circuit B _OUT C input circuit C _IN C output circuit C _OUT E input circuit E _IN And E output circuit E _OUT F input circuit F _IN And F output circuit F _OUT And three communication interfaces P1, P2, P3.

As such, the joint control system 21 is coupled to the arm controller 4 to receive the input data D _IN (i.e., the first arm monitor signal or the second arm monitor signal) to temporarily store the first arm monitor signal or the second arm monitor signal in the first temporary storage circuit 30 or the second temporary storage circuit 31. The joint safety system 23 is coupled to the joint control system 21, and receives the first arm monitoring signal or the second arm monitoring signal according to a first joint interrupt signal S1 or a second joint interrupt signal S2 to control the operation of the joint module 2. Next, the joint safety system 23 monitors the operation of the joint module 2 according to the synchronization signal SYNC (i.e. the joint synchronization signal), and generates a first joint monitoring signal and a second joint monitoring signal, which are temporarily stored in the temporary storage circuits 32, 3 for obtaining the operation of the joint module 2. Thereafter, the joint control system 21 generates a third joint interrupt message according to the third joint interrupt messageNumber S3 or fourth joint interruption signal S4, the first joint monitoring signal and the second joint monitoring signal are sequentially received from the joint safety system 23. Wherein the joint control system 21 can transmit the output data D _OUT (first joint monitoring signal and second joint monitoring signal) to the arm controller 4. The signal transmission between the joint control system 21 and the joint safety system 23 is performed via the communication interfaces P1 and P2 or via the communication interfaces P1 and P3, wherein the first monitoring module 24 and the second monitoring module 25 can sequentially or simultaneously transmit signals to the joint control system 21.

Referring to FIG. 5, the first to fourth joint interrupt signals S1 to S4 are respectively outputted from the A output circuit A _OUT To the A input circuit A _IN C output circuit C _OUT To C input circuit C _IN B output circuit B _OUT To B input circuit B _IN E output circuit E _OUT To E input circuit E _IN And the notification triggers the start of signal transmission. Similarly, the synchronization signal SYNC is formed by the F output circuit F _OUT To F input circuit F _IN The first monitoring module 24 and the second monitoring module 25 are triggered to monitor the electrical characteristics or the operation state of the mechanical appliance at the same monitoring time, wherein the first monitoring module 24 may trigger the second monitoring module 25 or the second monitoring module 25 may trigger the first monitoring module 24. In addition, the triggering of the joint safety system 23 may also be caused by the first joint interruption signal S1 or the second joint interruption signal S2, that is, after the first joint interruption signal S1 or the second joint interruption signal S2 triggers the synchronization signal SYNC (joint synchronization signal), the joint safety system 23 is controlled to monitor the operation of the joint module 2. In other words, the first joint interrupt signal S1 (or the second joint interrupt signal S2) may be used to control the joint control system 21 to output signals and the joint safety system 23 to monitor the mechanical implement synchronously. The various embodiments described above are optional and are not limited by examples.

Furthermore, when the control system and the safety system are disposed in the arm controller 4, the arm control system and the arm safety system, and the interrupt signals may be modified as arm interrupt signals, and the synchronization signals may be modified as arm synchronization signals. Thus, the method is applicable to a variety of applications. The arm control system 26 receives a first system monitor signal or a second system monitor signal to temporarily store the first system monitor signal or the second system monitor signal, wherein if the monitor signal is provided by the joint module 2, the first system monitor signal and the second system monitor signal may be referred to as a first joint monitor signal and a second joint monitor signal, which are just differences in names, without affecting the operation of the arm control system 26. The arm control system 26 is coupled to the arm safety system 27, and the arm safety system 27 receives the first system monitoring signal or the second system monitoring signal according to a first arm interrupt signal or a second arm interrupt signal to control the operation of the robot arm 1. The arm safety system 27 monitors the operation of the robot arm 1 according to the arm synchronization signal, and generates a first arm monitoring signal and a second arm monitoring signal. Likewise, the first arm interrupt signal (or the second arm interrupt signal) may trigger an arm synchronization signal to control the arm security system 27 to monitor the operation of the robot arm 1. The remaining description is not repeated as the control system and the safety system are provided in the joint module 2 as described above.

Please refer to fig. 6, which is a second circuit diagram of the control system and the safety system of the present invention. The embodiment of fig. 6 is different from the embodiment of fig. 5 in that the safety system in the embodiment of fig. 6 directly transmits the monitoring signals to the arm controller 4, that is, the first monitoring module 24 and the second monitoring module 25 directly transmit the first monitoring signal and the second monitoring signal to the first microprocessor 41 and the second microprocessor 42.

In summary, the mechanical apparatus of the present invention includes a control system and a safety system. The safety system is coupled with the control system, monitors the operation of the mechanical appliance, and generates a first monitoring signal and a second monitoring signal according to a synchronization signal, wherein the first monitoring signal and the second monitoring signal are obtained by monitoring the mechanical appliance at the same monitoring time.

Or the control system comprises a first temporary storage circuit and a second temporary storage circuit, and the first input data and the second input data are respectively temporarily stored. The communication control module controls the control system to output the first input data or the second input data. The safety system comprises a first monitoring module and a second monitoring module, wherein the first monitoring module is coupled with the first temporary storage circuit through a communication interface, and the second monitoring module is coupled with the second temporary storage circuit so as to sequentially receive first input data and second input data. The first monitoring module and the second monitoring module respectively comprise a synchronous circuit, and the synchronous signal controls the synchronous circuit to trigger the first monitoring module and the second monitoring module to detect the state of the mechanical appliance at the same monitoring time so as to generate a first monitoring signal and a second monitoring signal. The safety system outputs first output data and second output data according to the first monitoring signal and the second monitoring signal.

The above-mentioned embodiments are only for convenience of explanation, the scope of the invention is not limited to the embodiments, and any modification made in the present invention will fall within the scope of the claims of the present invention without departing from the spirit of the invention.

Claims (10)

1. A mechanical appliance, comprising:

a control system; a kind of electronic device with high-pressure air-conditioning system

The safety system is coupled with the control system, monitors the operation of the mechanical appliance, and generates a first monitoring signal and a second monitoring signal according to the synchronous signal, wherein the first monitoring signal and the second monitoring signal are obtained by monitoring the mechanical appliance at the same monitoring time.

2. The robotic device of claim 1, wherein the robotic device is a robotic arm, an arm controller of the robotic arm comprising the control system and the safety system.

3. The mechanical appliance of claim 2, wherein the control system is an arm control system, the safety system is an arm safety system, and the arm control system receives a first system monitoring signal or a second system monitoring signal to temporarily store the first system monitoring signal or the second system monitoring signal; the arm control system is coupled to the arm safety system, and the arm safety system receives the first system monitoring signal or the second system monitoring signal according to the first arm interrupt signal or the second arm interrupt signal to control the operation of the mechanical arm.

4. The robot of claim 3, wherein the synchronization signal is an arm synchronization signal, and the arm security system monitors operation of the robot based on the arm synchronization signal to generate a first arm monitor signal and a second arm monitor signal.

5. The robot of claim 4, wherein the first arm interrupt signal or the second arm interrupt signal triggers the arm sync signal to control the arm safety system to monitor the operation of the robot.

6. The mechanical device of claim 1, wherein the mechanical device is a robotic arm, each joint module of the robotic arm comprising the control system and the safety system.

7. The mechanical appliance of claim 6, wherein the control system is an articulation control system, the safety system is an articulation safety system, the articulation control system receives a first system monitoring signal or a second system monitoring signal to temporarily store the first system monitoring signal or the second system monitoring signal; the joint control system is coupled with the joint safety system, and the joint safety system receives the first system monitoring signal or the second system monitoring signal according to the first joint interrupt signal or the second joint interrupt signal so as to control the operation of the joint module.

8. The mechanical apparatus of claim 7, wherein the synchronization signal is a joint synchronization signal, and the joint safety system monitors the operation of the joint module according to the joint synchronization signal to generate a first joint monitoring signal and a second joint monitoring signal to obtain the operation of the joint module.

9. The mechanical appliance of claim 8, wherein the first joint interrupt signal or the second joint interrupt signal triggers the joint synchronization signal to control the joint safety system to monitor the operation of the joint module.

10. The mechanical appliance of claim 1, comprising:

the control system comprises a first temporary storage circuit and a second temporary storage circuit, wherein the first temporary storage circuit and the second temporary storage circuit respectively temporarily store first input data and second input data;

the communication control module controls the control system to output the first input data or the second input data; a kind of electronic device with high-pressure air-conditioning system

The safety system comprises a first monitoring module and a second monitoring module, wherein the first monitoring module is coupled with the first temporary storage circuit through a communication interface, and the second monitoring module is coupled with the second temporary storage circuit so as to sequentially receive the first input data and the second input data; the first monitoring module and the second monitoring module respectively comprise a synchronous circuit, and the synchronous signal controls the synchronous circuit to trigger the first monitoring module and the second monitoring module to detect the state of the mechanical appliance at the same monitoring time so as to generate a first monitoring signal and a second monitoring signal; the safety system outputs first output data and second output data according to the first monitoring signal and the second monitoring signal.