CLIAMS:We claim:
1. A system for the automated verification and validation of motor control firmware of an embedded system, the system comprising:
? a motor (101) without load, wherein the motor comprises of an extended shaft (102);
? an electromagnetic brake (103) for stopping the motor (101) is attached to the extended shaft (102);
? an optical encoder (109) for detecting the position of the motor (101), wherein a shaft emanating from the electromagnetic brake (103) is connected to a shaft of the optical encoder (109); and
? a real time embedded simulator (110) for simulating and receiving real time signals.
2. The system as claimed in claim 1, wherein the system further comprises a first coupler (104) for connecting an electromagnetic brake shaft to the extended shaft of the motor.
3. The system as claimed in claim 1, wherein the system further comprises a second coupler (107) for connecting the optical encoder shaft to the shaft emanating from the electromagnetic brake (103).
4. The system as claimed in claim 1, wherein the real time embedded simulator comprises of:
? a processor card (112) operating in transistor-transistor logic (TTL) voltage levels;
? an Input Output (I/O) card (114) to handle plurality of signals including, digital signal, analog signal and Pulse Width Modulation (PWM) signal; and
? a signal conditioning card to translate TTL voltage level to real world values and vice versa;
wherein the electromagnetic brake (103) is controlled by an analog output pin of the I/O card (114) based on the input from the processor card (112).
5. The system as claimed in claim 1, wherein the system further comprises a time control block to control the duration of braking.
6. A method for automated verification and validation of a motor control firmware of an embedded system, wherein the method comprising the steps of:
a. connecting the embedded system to at least one motor, wherein the motor comprises an extended shaft connected to a shaft of an electromagnetic brake, wherein the shaft emanating from the electromagnetic brake is connected to a shaft of an optical encoder;
b. driving the motor through the embedded system in accordance with the input simulation from a real time embedded simulator in accordance with a type of validation or verification;
c. applying an electromagnetic brake control signal through an I/O card of the real time embedded simulator in accordance with the type of validation or verification;
d. analyzing the input signals simulated from the real time embedded simulator for the embedded system to drive the motor and the signals from the optical encoder for the type of validation or verification, wherein the signals from the optical encoder identifies the current position of the motor in accordance with the type of verification or validation.

7. The method as claimed in claim 6, wherein the method of validation or verification is anti pinch validation, wherein the step of applying the electromagnetic brake control signal is with maximum force for short duration while the motor is moving in usual travel limit.
8. The method as claimed in claim 7, wherein the step of analyzing verifies whether motor position decoded from the optical encoder pulses is increasing if the motor position was previously decreasing or decreasing if the motor position was previously increasing.
9. The method as claimed in claim 6, wherein the method of validation or verification is of soft stop feature, wherein the real time embedded simulator generates the control signals of a switch pack for the motor control firmware of the embedded system for moving the motor in one direction continuously.
10. The method as claimed in claim 9, the step of analyzing verifies whether the motor which moves in its usual travel limit and stopped by the embedded system at a position, wherein the position decoded from the optical encoder pulses is equal to the pre-saved soft stop position.
11. The method as claimed in claim 6, wherein the method of validation or verification is of stall detection, wherein the electromagnetic brake control signal applies brake for a long duration with full force while the motor is moving in usual travel limit.
12. The method as claimed in claim 11, wherein the step of analyzing verifies whether the motor position decoded from optical encoder do not change as soon as the brakes are released.
13. The method as claimed in claim 6, wherein the method of validation or verification is of hard end detection, wherein the electromagnetic brake control signal applies brake for a long duration with full force while the motor is moving outside its usual travel limit, wherein the electromagnetic brake control signal applies brake at the pre-known hard end position.
14. The method as claimed in claim 13, wherein the step of analyzing verifies whether the motor position decoded from optical encoder does not change as soon as the brakes are released.
15. The method as claimed in claim 6, wherein the method of validation or verification is of position detection, wherein the step of driving the motor drives the motor for ‘n’ seconds.
16. The method as claimed in claim 15, wherein the step of analyzing compares the change in the motor position count obtained by decoding the optical encoder pulses with change in the motor position count received from a debug port of the embedded system through the debug port interface of the real time embedded simulator.
17. The method as claimed in claim 6, wherein the method of validation or verification is of overload detection, wherein the overload condition of the motor is created by applying a reduced supply voltage input to electromagnetic brake while the motor is moving; where the percentage of applied voltage to brake with respect to the actual nominal voltage of the brake determines the amount of overload applied.
18. The method as claimed in claim 17, wherein the step of analyzing compares the behavior of motor control firmware of the embedded system with the requirement.
19. The method as claimed in claim 6, wherein the method of validation or verification is of position control, the motor is being driven for n seconds.
20. The method as claimed in claim 19, wherein the step of analyzing decodes the optical encoder pulses to decode the position to verify whether the motor position and movement is correctly controlled by the motor control firmware of the embedded system and further calculates the motor speed in Rotation per Minute (RPM) using the data received form optical encoder to compare the motor speed against the speed requested by the motor control firmware of the embedded system.
21. The method as claimed in claim 6, wherein the method of validation or verification is of calibration, wherein the step of driving the motor is performed in one direction continuously by the motor control firmware of the embedded system, whereby brake is applied by the real time embedded simulator with full force and long duration until when the motor position decoded from encoder pulses is equal to the expected hard end position
22. The method as claimed in claim 22, wherein the step of analyzing is performed by reading the hard end positions stored in the non volatile memory of ECU through debug port interface of real time embedded simulator to analyze the similarity between the read hard end position with the expected hard end positions.
,TagSPECI:[001] DESCRIPTION OF THE INVENTION
[002] The following specification particularly describes the invention and the manner in which it is to be performed:

[003] FIELD OF THE INVENTION
[004] The present invention relates to a system and method for automatic validation of motor control firmware of an embedded system. More particularly, the invention helps in automatically validating a number of motor controls in a test bench.

[005] BACK GROUND OF INVENTION
[006] Modern day motors used in various applications are strategically controlled by an embedded system, using the firmware stored in it, based on the combination of different real time input signals like switch inputs, current drawn by the motor, voltage variations and motor position feedback information etc. In addition to these functional requirements, embedded systems also execute safety related features such as anti pinch, detection of obstruction etc.
[007] Some motors are usually stopped by the embedded system before it reaches a mechanical end. This position is usually called first stop or soft stop and the embedded system depends on the current motor position decoded from position sensors or sensor less positioning system for identifying the soft stop. Identifying the soft stop avoids unwanted current shoot ups in the motor control lines. If the motor is made to move in the same direction beyond the soft stop, it will be stopped by the embedded system at the mechanical end called a hard stop or a second stop. Embedded system relies on the current motor position and current shoot up in the motor control lines for identifying the hard end. If this mechanical stop is detected during the usual travel limit of the motor which is in between the soft stops of either direction, it is considered as a stall and motor is stopped to avoid over-heating, this is called as stall detection. Embedded system relies on current motor position and current shoot up graph for identifying stall also. If some obstacle, for example: Hand of a user is trapped in between the moving motor or its loads, embedded system detects a pinch and causes the motor to retract back in opposite direction, and this feature is called as anti-pinch. Embedded system and its firmware may detect current levels beyond thresholds during normal movement of motor which results in the execution of specific actions and setting the corresponding fault codes, this is called as overload detection. Current shoot up rate may be more for a mechanical obstacle as compared to a human body part.
[008] Embedded systems like seat Electronic Control Unit (ECU) used in automobiles have a calibration routine which when executed through automotive protocols like Controller Area Network (CAN) or Local Interconnect Network (LIN), automatically moves motors continuously and based on current shoot up, stores the hard end positions of either directions of movement in non volatile memory of the ECU. This calibration routine may be executed once by the manufacturer or by the service engineers if calibration is lost.
[009] Certain embedded systems control multiple motors connected to it at the same time based on a set of functional requirements. Memory recall feature used by automobile seat ECU is an example. Here, seat ECU moves multiple motors connected to different axis of movements of seat at the same time when the passenger presses a memory recall button thereby moving the seat to a position which was pre saved before. ECU shall make use of pre saved memory recall positions of each seat axis motor stored in the non-volatile memory of the ECU for implementing this feature.
[010] Embedded system shall rely on current motor position for the implementation of these control algorithms which is calculated based on the sensor waveforms emanating from the motors or using sensor less positioning system where embedded system can know the current motor position based on the back EMF sensed on the motor control lines. Embedded system stores the expected travel ranges of each motor in its non volatile memory. This shall be used as a reference for checking the soft stop, hard end, stall and anti-pinch. There are existing systems that are used for validation of particular motor control firmware whereas most of them can be used only for a particular situation and the way in which such verification happens are more in the physical hardware parts and not in the manner in which it works.
[011] The European Patent application EP1775829 discloses a servo motor controller for controlling a servo motor for rotationally driving a joint portion of an un-shown multi-joint type industrial robot, including a motor control section electrically interconnected to the servo motor via the servo amplifier, and a braking circuit controlled by the motor control section for ON/OFF switching of an electromagnetic brake (brake) and an encoder as a position detector for detecting the position information of the motor. This invention, applicable only to servo motors, is not designed for the purpose of real time motor control algorithm validation. It discloses the design of a servo motor controller where interconnection details of motor, brake and encoder are not considered.
[012] The European Patent application EP1710549 A2 discloses a method of testing the brakes of a motor of a robot, in which the motor comprises a brake, in which the shaft of the engine extends by the brake, the shaft of the motor can be braked. The position of the shaft is detected by a position encoder. This invention was designed for verifying the brakes, not motor control algorithms.
[013] The United States Patent no US5218860 discusses about method of testing the torque characteristics of an electric motor (not the motor control algorithm) including the steps of attaching the shaft of an electric motor to a known inertial load, supplying power to the motor at a specified time, measuring the amount of rotation of the motor shaft within known time intervals, calculating the motor's torque by reference to the inertial load and the amount of motor shaft rotation within each of the time intervals, and displaying the motor's torque with reference to the speed of the motor shaft. Here, inertial load in the form of flywheel is attached to motor shaft for creating loading effect. No automated braking option is provided in the prior art. Incremental encoder is known to provide low accuracy and durability.
[014] The United States Patent no US5404108 has put forward a testing apparatus for rotors of electric motors comprising a test fixture including a fixture shaft on which a rotor is temporarily attached to a known inertial load. A stator creates a rotating magnetic field to cause rotation of the rotor, and an encoder senses the amount of angular rotation of the rotor in short time intervals, which is recorded in a memory and later used to calculate torque. Here, a constant inertial load was given to motor under interest with no option for automation or variation of load.
[015] Hence, there is need for a system and method to overcome the various shortcomings in the prior arts and to have an automated test bench for the validation of various motor control firmware of an embedded system.
[016] SUMMARY OF THE INVENTION
[017] The invention discloses a system and method for automated verification and validation of motor control firmware of an embedded system. According to an embodiment, the system includes a motor without load, wherein the motor includes an extended shaft. The system also includes an electromagnetic brake for stopping the motor and an optical encoder for detecting the position of the motor, wherein a shaft emanating from the electromagnetic brake is connected to a shaft of the optical encoder. The system further includes a real time embedded simulator for simulating and receiving real time signals.
[018] According to another embodiment of the invention, the system further includes a first coupler for connecting an electromagnetic brake shaft to the extended shaft of the motor. The system also has a second coupler for connecting the optical encoder shaft to the shaft emanating from the electromagnetic brake.
[019] According to another embodiment, the real time embedded simulator includes a processor card operating in transistor-transistor logic (TTL) voltage levels and an Input Output (I/O) card to handle plurality of signals including, digital signal, analog signal and pulse width modulation (PWM) signal. The real time embedded simulator further includes a signal conditioning card to translate TTL voltage level to real world values and vice versa. The electromagnetic brake may be controlled by an analog output pin of the I/O card based on the input from the processor card. The current position of the motor may be calculated using optical encoder pulses by the real time embedded simulator. The system further includes a time control block to control the duration of braking.
[020] According to another embodiment, the invention discloses a method for automated verification and validation of a motor control firmware of an embedded system. The method includes the steps of connecting the embedded system to at least one motor, wherein the motor comprises an extended shaft connected to a shaft of an electromagnetic brake, wherein the shaft emanating from the electromagnetic brake is connected to a shaft of an optical encoder. The method further includes a step of driving the motor through the embedded system in accordance with the input simulation from a real time embedded simulator in accordance with a type of validation or verification. The method also includes a step of analyzing the input signals simulated from the real time embedded simulator for the embedded system to drive the motor and the signals from the optical encoder for the type of validation or verification, wherein the signals from the optical encoder identifies the current position of the motor in accordance with the type of verification or validation.
[021] According to another embodiment, the method of validation or verification is anti pinch validation, wherein the step of applying the electromagnetic brake control signal is with maximum force for short duration while the motor is moving in usual travel limit which is within the soft stop position in either axis. The step of analyzing verifies whether the motor position decoded from optical encoder pulses is increasing, if motor position was previously decreasing or decreasing, if it was previously increasing.
[022] According to another embodiment, the method of validation or verification is of soft stop feature, wherein the real time embedded simulator generates the control signals of a switch pack for the motor control firmware of the embedded system for moving the motor in one direction continuously. The step of analyzing verifies whether the motor which is moving in its usual travel limit when stopped by the embedded system at a position, wherein the position decoded from the optical encoder pulses is equal to the pre-saved soft stop position.
[023] According to another embodiment, the method of validation or verification is of stall detection, wherein the step of applying the electromagnetic brake control signal applies brake for a long duration with full force while the motor is moving in usual travel limit which is within the soft stop position in either axis. The step of analyzing verifies whether the motor position decoded from optical encoder do not change as soon as the brakes are released.
[024] According to another embodiment, the method of validation or verification is of hard end detection, wherein the electromagnetic brake control signal applies brake for a long duration with full force while the motor is moving outside its usual travel limit, wherein the step of applying the electromagnetic brake control signal applies brake at the pre-known hard end position. The step of analyzing verifies whether the motor position decoded from optical encoder does not change as soon as the brakes are released.
[025] According to another embodiment, the method of validation or verification is of position detection, wherein the step of driving the motor drives the motor for n seconds. The step of analyzing compares the change in the motor position count obtained by decoding the optical encoder pulses with change in the motor position count received from a debug port of the embedded system through the debug port interface of the real time embedded simulator for n seconds.
[026] According to another embodiment, the method of validation or verification is of overload detection, wherein the overload condition of the motor is created by reducing supply voltage input to electromagnetic brake; where the percentage of applied voltage to brake with respect to the actual nominal voltage of the brake determines the amount of overload applied. The step of analyzing compares the behavior of the embedded system with the requirement and setting of the relevant fault codes.
[027] According to another embodiment, the method of validation or verification is of position and speed control, wherein the motor is driven for n seconds. The step of analyzing analyses the optical encoder pulses to decode the position to verify whether the motor position and movement is correctly controlled by the motor control firmware of the embedded system. The step of analyzing calculates the motor speed in Rotation per Minute (RPM) using the data received form optical encoder and the step of analyzing further compares the motor speed against the speed requested by the motor control firmware of the embedded system.
[028] According to an embodiment, the method of validation or verification is of calibration. The step of driving the motor is performed in one direction continuously by the motor control firmware of the embedded system, whereby brake is applied by the real time embedded simulator with full force and long duration until when the motor position decoded from encoder pulses is equal to the expected hard end position. The step of analyzing is performed by reading the hard end positions stored in the non volatile memory of ECU through debug port interface of real time embedded simulator to analyze its similarity with the expected hard end positions.
[029] The present invention provides a mechanical system and methods for the proper and early validation of motor control algorithms in a closed loop environment by simulating the real world conditions in its entirety. This allows developers to validate and verify control algorithms early in the design cycle which improves control specification quality and reduces overall cost and time for embedded product design.
[030] BRIEF DESCRIPTION OF THE DRAWINGS
[031] FIG. 1 illustrates the instrumentation fixture (which is a part of the test bench) used for the validation of motor control firmware of an embedded system.
[032] FIG. 2 illustrates the architecture of the system, in accordance with an embodiment of the invention.
[033] FIG. 3 and FIG 4 illustrate the output of channel A and channel B of the optical encoder in case of clockwise motion and anti clockwise motion of the motor shaft respectively, in accordance with an embodiment of the invention.
[034] FIG 5 illustrates a flow chart of the method, in accordance with an embodiment of the invention.
[035] DETAILED DESCRIPTION
[036] Reference will now be made in detail to the description of the present subject matter, one or more examples of which are shown in figures. Each example is provided to explain the subject matter and not a limitation. Various changes and modifications obvious to one skilled in the art to which the invention pertains are deemed to be within the spirit, scope and contemplation of the invention.
[037] The term “Usual Travel Limit” used herein refers to the travel of motor between the soft stop in either axis.
[038] Before describing in detail, the embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily for testing of a motor control firmware of an embedded system used for controlling motors. The invention discloses a system and method for automated verification and validation of motor control firmware of an embedded system.
[039] According to an embodiment, the invention discloses a system for verification and validation of motor control firmware of an embedded system. FIG 1 illustrates the instrumentation fixture (which is part of the test bench) used for the verification and validation of motor control firmware of the embedded system. The system includes a motor (101) without load; the motor (101) comprises an extended shaft (102). The system also includes an electromagnetic brake (103) for stopping the motor. The electromagnetic brake (103) is attached to the extended shaft (102). In most of the scenario the bore size of the electromagnetic brake (103) and the size of the extended shaft (102) may be different. The difference in the size of the extended shaft (102) and electromagnetic brake (103) shaft may be compensated by a first coupler (104). The first coupler (104) may be metallic. The electromagnetic brake (103) may be a DC electromagnetic brake. The electromagnetic brake (103) may have a moving part and a static part. The static part shall be strongly fixed to a base frame (106) made of aluminum using the metal leg (105). The moving part may be connected to the extended shaft (102) and the rotation of the motor (101) cause the moving part of the electromagnetic brake (103) to rotate. Stopping torque of DC electromagnetic brake (103) should generally be greater than maximum torque of motor (101) under interest. The static part of the electromagnetic brake (103) is an electromagnet. When a DC supply is given to the electromagnet, the electromagnet is magnetized to result in the attraction of the moving part towards static part thereby preventing further motion. The stopping torque of the electromagnet may be reduced proportionally by applying DC supply which is less than its rated supply voltage. Maximum stopping torque occurs when the rated voltage is given at the supply lines of the brake.
[040] The system may also include an optical encoder (109) for detecting the position of the motor (101). The shaft emanating from the electromagnetic brake (103) is connected to a shaft of the optical encoder (109). The optical encoder (109) may convert the mechanical motion of the motor extended shaft (102) to corresponding electrical pulses. The direction of rotation and the position of the motor extended shaft (102) are determined from the electrical pulses of the optical encoder (109). A second coupler (107) is employed between the shaft emanating from the electromagnetic brake (103) and the encoder shaft to take care of size mismatches between them. All the components including the motor (101), electromagnetic brake (103), the optical encoder (109) may be fixed to an aluminum frame (106). The whole arrangement of the components to the aluminum frame (106) is together referred as instrumentation fixture. More than one such assembly of motor, electromagnetic brake and optical encoder may be fixed to the same fixture for the validation of simultaneous motor control requirements. Many times in an embedded system, more than one motor needs to be controlled by the embedded system simultaneously. Such types of requirements may be verified by using more than one assembly in a single fixture. The system also includes a real time embedded simulator (110) for simulating and receiving real time signals. The real time embedded simulator (110) is herein after referred as embedded simulator.
[041] According to an embodiment, the embedded simulator includes a processor card operating in TTL voltage levels. The embedded simulator also includes an I/O card to handle plurality of signals including, digital signal, analog signal and pulse width modulation (PWM) signal; and a signal conditioning card to translate TTL voltage level to real world values and vice versa.
[042] FIG. 2 illustrates the architecture of the system, in accordance with an embodiment of the invention. The embedded simulator (110) has a modular architecture comprising of a processor card (112) operating in TTL voltage levels, I/O cards (114) capable of handling digital, analog and PWM signals and a signal conditioning card which translates voltage level from TTL to real world values and vice versa. The processor card (112) has the logic for the whole test assembly which controls the relevant pins of the I/O Card (114). The I/O card (114) of the embedded simulator (110) may provide button press simulation (110a) and protocol simulation (110b) to the embedded system. The I/O card (114) of the embedded simulator (110) may also provide brake control signal (110c) to the electromagnetic brake (103). The embedded simulator (110) may receive input from the debug port interface (110d) from the embedded system and receives optical encoder pulses (110e) from the optical encoder (109). The embedded system may provide motor control signal (115a) directly to the motor (101) and may receive the motor sensor feedback (115b).
[043] The embedded system (115) is driving the motor (101) directly. The motor control firmware in embedded system (115) is sensing the current motor position using the sensor feedback from the motor itself. In case of modern motor controllers, sensor less positioning is employed which makes use of back EMF for sensing current motor position. Instead of the sensor pulses from the motor, the present invention is making use of more accurate high duty optical encoder pulses. This is accomplished by wiring the output of optical encoder (109), which is digital pulse to digital input pins in the I/O card (114). The electromagnetic brake (103) may be controlled by high current analog output pin of the I/O card (114). There is a high speed bidirectional internal communication between the processor card (112) and the I/O card (114) of the embedded simulator (110) hardware. In this way the processor card (112) may be capable of applying the electromagnetic brake (103) at its discretion. The processor card (112) is also capable of calculating the current motor position as it is receiving optical encoder pulses.
[044] According to an embodiment, the system uses an optical encoder (109) to translate the mechanical rotation of extended shaft (102) into electrical pulses. The optical encoder helps in position detection of motor (101) equipped with sensor less positioning feature also. This is a cost effective solution, as decoding the position using sensor less positioning, which makes use of back EMF requires complex circuitry and time consuming computations. Since the system is not relying on hall sensor inside the motor or the back EMF of motor, it can also point out the irregularities in the motor and the sensor used in motor. Industry standard rugged optical encoder with a very high pulse per revolution (1024 PPR) is used in the test bench. FIG. 3 and 4 illustrate the output of channel A and channel B of the optical encoder in case of clockwise motion and anti clockwise motion of the motor shaft respectively, in accordance with an embodiment of the invention. The optical encoder (109) is having two output digital lines which give electrical pulses whose rising edges show change in the position of motor shaft. Referring to FIG. 3 output of optical encoder in case of clockwise motion, it is seen that Channel B leads Channel A by 90º while the duty cycle of both the waveforms remains the same. Referring to Figure 4, output of optical encoder in case of anti clockwise motion, can be seen that Channel A leads Channel B by 90º while the duty cycle of both the waveforms remains the same. Rising edge of both the waveforms indicate the change in motor position while phase difference shows direction of travel. Channel A and Channel B are wired to digital input of simulator. The embedded simulator detects motor position from optical encoder pulses. The embedded simulator increments the motor position count when there is rising edge in Channel A and a high value in Channel B of the optical encoder pulse. Similarly, the embedded simulator decrements the motor position count when there is rising edge in Channel B and a high value in Channel A. Current position of the motor may be fed into the validation algorithms.
[045] According to another embodiment, the invention discloses a method for automated verification and validation of a motor control firmware of an embedded system. FIG 5 illustrates a flow chart of the method, in accordance with an embodiment of the invention. The method includes the step (502) of connecting the embedded system to drive a motor (101), wherein the motor (101) includes an extended shaft (102) connected to an electromagnetic brake (103). The shaft emanating from the electromagnetic brake (103) is connected to a shaft of an optical encoder (109). The method further includes a step (504) of driving the motor (101) through the embedded system in accordance with the input simulation from an *embedded simulator (110) in accordance with a type of validation or verification. The method further includes a step (506) of applying an electromagnetic brake control signal through an I/O card of the embedded simulator (110) in accordance with the type of validation or verification The method further includes a step (508) of analyzing the input signals simulated from the embedded simulator (110) for the embedded system to drive the motor (101) and the signals from the optical encoder (109) for the type of validation or verification, wherein the signals from the optical encoder (109) identifies the current position of the motor (101) in accordance with the type of verification or validation.
[046] According to an embodiment, the method of validation or verification is anti pinch validation. The step of applying the electromagnetic brake control signal is performed in such a way that the electromagnetic brake applies a maximum force for short duration while the motor is moving in usual travel limit. The brake control signal emanating from the embedded simulator may be going to a timing control block, which controls duration for which the brake is to be applied, wherein the brake control signal subsequently comes out of the analog output of embedded simulator. A human body part obstacle and a real mechanical obstacle may cause different current shoot up for a motor. Anti pinch validation makes use of brake applied for lesser duration. Once the brake is applied, after ‘n’ milliseconds if the motor is made to rotate in opposite direction by the embedded system as compared to its previous motion, anti pinch validation is said to be ‘PASSED’. The step of analyzing verifies whether the motor position decoded from the optical encoder pulses is increasing if the motor position was previously decreasing or decreasing if the motor position was previously increasing. Test system is also capable of validating the amount by which the motor retracted and the time it took for the same by utilizing change of motor position value and a timer.
[047] According to an embodiment, the method of validation or verification is of soft stop feature. The embedded simulator gets the pre-saved soft stop position from the embedded system by reading through the debug port of the embedded system. The soft stop position is stored (pre-saved) in the embedded simulator. Usually, users control the embedded system through a switch pack which is either hardwired or interfaced using specific protocols. The present invention uses no real switch therefore the control signal may be simulated from the embedded simulator hardware. If the switch simulation is in on position; the motor is in the usual travel limit and the motor is made to stop at the pre-saved soft stop position by the embedded system, then the soft stop validation is said to be ‘PASSED’. The embedded simulator generates the control signals of a switch pack for the embedded system for moving the motor in one direction continuously. The step of analyzing verifies whether the motor which is moving in its usual travel limit when stopped by the embedded system at a position, wherein the position decoded from the optical encoder pulses is equal to the pre-saved soft stop position.
[048] According to an embodiment, the method of validation or verification is of stall detection. The electromagnetic brake control signal applies brake for a longer duration with full force while the motor was moving in usual travel limit. The step of analyzing verifies whether the motor position decoded from optical encoder do not change as soon as the brakes are released.
[049] According to an embodiment, the method of validation or verification is of hard end detection. The electromagnetic brake control signal applies brake for a long duration with full force while the motor is moving outside its usual travel limit, wherein the step of applying the electromagnetic brake control signal applies brake at the pre-known hard end position. If this causes the motor to stop completely, hard end detection is said to be ‘PASSED’. The embedded simulator receives the pre-known hard end position from the debug port interface of the embedded system. The step of analyzing verifies whether the motor position decoded from optical encoder does not change as soon as the brakes are released.
[050] According to an embodiment, the method of validation or verification is of position detection of embedded system. The step of driving the motor drives the motor for n seconds. The n represent a minimum of 15 seconds to a maximum 300 seconds. The step of analyzing compares the change in the motor position count obtained by decoding the optical encoder pulses with change in the motor position count received from a debug port of the embedded system through the debug port interface of the embedded simulator for n seconds. For those motors, which are equipped with position detection sensors, this test solution may also be used for verifying the accuracy of sensors by comparing the counts from embedded simulator and from embedded system (through debug port interface) for the same travel range/time of operation. For those motors, which are equipped with sensor less positioning, same test solution can be used for verifying the accuracy of sensor less positioning algorithm by comparing the counts from embedded simulator and from embedded system (through debug port interface) for the same travel range/time of operation.
[051] According to an embodiment, the method of validation or verification is of overload detection. The overload scenario may be simulated by applying electromagnetic brakes partially while the motor is in motion. The overload condition of the motor is created by reducing supply voltage input to electromagnetic brake where the percentage of applied voltage to the brake with respect to the actual nominal voltage of the brake determines the amount of overload applied. The step of analyzing compares the behavior of the embedded system with the requirement provided and setting of the relevant fault codes. A lookup table in the embedded simulator may calculate the voltage required at the brake supply lines for the required braking torque / load.
[052] Basic requirement of most of the motor control systems is to control the motor position, movement and speed to the desired value at the request of button presses. Button presses needed by the embedded system controller may be simulated by the digital / analog output / protocol pins of the embedded simulator. Position decoded from the optical encoder pulses may be used to verify that the motor position, speed and movement is correctly controlled by the embedded system controller. According to an embodiment, the method of validation or verification is of position and speed control of the motor by the embedded system. The motor is driven for n seconds by the switch of the embedded simulator through the embedded system. The step of analyzing decodes the optical encoder pulses to decode the position to verify whether the motor position and movement is correctly controlled by the embedded system. The step of analyzing further calculates the motor speed in RPM using the data received form optical encoder and the step of analyzing further compares the motor speed against the speed requested by the embedded system. Motor speed in RPM is calculated by taking the ratio of calculated position increment or decrement in one minute to the pulse per revolution of optical encoder. Motor speed calculated by the test system is compared against the speed requested by the embedded system. This is especially helpful to modern day PWM controlled motors, where motors are run at different speeds by varying the PWM duty cycle.
[053] According to another embodiment, the method of validation or verification is of calibration routine. The step of driving the motor is performed in one direction continuously by the embedded system, whereby brake is applied by the embedded simulator with full force and long duration. During this the current motor position computed from optical encoder pulses should be equal to the pre saved expected calibration point. The step of analysis read the hard end positions stored in the non volatile memory of ECU through debug port interface of the embedded system to analyze the similarity between the read hard end positions with the expected hard end positions. The entire steps may be repeated for the opposite direction also.
[054] According to an embodiment, the system may be used with more than one assembly of motor, shaft, brake, and optical encoder. The embedded simulator may be capable of validating algorithms used for simultaneous control of such system where in more than one motor is working.
[055] Depending upon the intended application of the device and area of use, each motor control algorithm shall have different functional requirements. Test bench designed in a generic base is capable of validation and verification of any such requirements as the test engineer is given read and write access to embedded system control signals (button presses), current motor position value and brake control signals. One may use them in any sequential combination for proving out of different real world scenarios. 100% automation of test procedures may be ensured by the invention. Test script is prepared in a spreadsheet format according to validation requirements including all input variables like embedded system controlling button signal, brake control signal and all output variables like current motor position, motor status, and direction of motor rotation. Different combination of input signals and expected output signals may be entered in the test script which may be sequentially executed. Actual outputs shall be compared against the expected output in the test script to decide whether the test case is pass or fail. All this operations may be executed automatically without any manual intervention. A graphical user interface may also be provided to the test engineer for accessing the signals used in test bench control. This is useful for executing an in depth manual testing.
[056] Thus, the present invention provides a mechanical system and methods for the proper and early validation of motor control algorithms in a closed loop environment in an automated fashion by simulating the real world conditions in its entirety. This facilitates to validate and verify control algorithms early in the design cycle which improves control specification quality and reduces overall cost and time for embedded product design. The present invention is capable of performing the validations without manual intervention. This invention enables the effective implementation of the embedded system which avoids the product recall. The present invention is further capable of verification and validation of all types of motors with any type of position feedback.