Braking system for test vehicle

Abstract

This application is titled "Braking System for a Test Vehicle". A scootable test vehicle includes an electronically controlled anti-slip braking system for reducing wheel slip during rapid deceleration. The test vehicle comprises: a chassis; at least one electric motor connected to a first axle; a hydraulic braking system connected to the chassis and at least one second axle; a rotational speed sensor for determining the rotational speed of the connected axle; a ground speed sensor; and a controller connected to the electric motor, the hydraulic braking system, the rotational speed sensor, and the ground speed sensor. The controller is configured to calculate the difference between the rotational speed of the axle and the ground speed of the chassis to determine a wheel slip threshold, actuate the hydraulic braking system to apply a first braking force, and control at least one motor parameter of the electric motor to apply a second braking force. The combined first and second braking forces are less than the wheel slip threshold, causing the chassis to decelerate rapidly without wheel slip.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202010819670.1, entitled "Braking System for Test Vehicle," filed on August 14, 2020.

[0002] priority

[0003] This application claims priority to U.S. Provisional Patent Application No. 62 / 886,554, filed August 14, 2019, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0004] This application generally relates to braking systems for advanced crash test vehicles, particularly overpass test vehicles (OTVs). Background Technology

[0005] With the rise of Advanced Driver Assistance Systems (ADAS) under development and testing, the demand for testing equipment that reduces risk to test personnel and can withstand potentially damaging impacts and scenarios has increased dramatically. The most important tool for testing emerging collision avoidance technologies is the use of mobile and controllable platforms. Mobile platforms are suitable for holding simulated target objects, such as cars, trucks, pedestrians, bicycles, or similar objects. Simulated targets are typically made of materials that will not damage the vehicle equipped with ADAS, such as foam, cardboard, or any other soft material.

[0006] During testing, the mobile test platform may be subjected to sudden or forceful braking to test the collision avoidance technology integrated into the passenger vehicle. Typically, the braking system on the test vehicle is applied when the master cylinder initiates the closure of the brake chuck on the brake rotor. The magnitude of the force applied by the brake chuck is monitored using pressure sensors. However, only the applied pressure is monitored, without data on the wheel rotation speed. If the wheel rotation speed is not measured when the test vehicle decelerates, the brake chuck may apply too much pressure to the brake rotor, causing wheel lock-up and resulting in vehicle slippage.

[0007] During deceleration, the tires of the test vehicle may lock up, causing wheel slippage. In some cases, the wheel may lock up and burst due to slipping conditions. Wheel slippage occurs when the force applied to the tire (i.e., braking torque) exceeds the tire's available traction. Braking torque is the magnitude of the force applied by the brake calipers to the brake rotor and subsequently to the wheel and tire. When the braking torque is too high, the tire will lock up, and the vehicle may begin to slip in unpredictable ways.

[0008] A braking system that monitors the pressure applied to the brake rotor from the brake caliper and monitors the speed of the peripheral wheels and the chassis would be very attractive. A braking system that actively monitors braking force and wheel speed to prevent wheel slippage would also be very attractive. Summary of the Invention

[0009] This application provides a braking system that monitors and analyzes the difference between wheel speed and chassis speed, and calculates the optimal braking force to prevent wheel slippage during deceleration. This braking system applies optimal force to the wheels.

[0010] This application provides a hop-through test vehicle including an electronically controlled anti-skid braking system for reducing wheel slippage during rapid deceleration. The hop-through test vehicle further includes: a chassis; a first and second axle rotatably supported by the chassis; wheels connected to each of the first and second axles; at least one electric motor connected to the first axle; a hydraulic braking system partially supported by the chassis and partially coupled to at least the second axle; a rotational speed sensor connected to at least one of the first and second axles for determining the rotational speed of the connected axle; a ground speed sensor supported by the chassis for determining the ground speed of the chassis; and a controller operatively connected to at least one electric motor, the hydraulic braking system, the rotational speed sensor, and the ground speed sensor, the controller being configured to: calculate the difference between the rotational speed of the axle and the ground speed of the chassis to determine a wheel slippage threshold; actuate the hydraulic braking system to apply a first braking force; control at least one motor parameter of the at least one electric motor to apply a second braking force; wherein the combined first and second braking forces are less than the wheel slippage threshold, causing the chassis to decelerate rapidly in the absence of wheel slippage.

[0011] The traverseable test vehicle also features a rotational speed sensor directly connected to the second axle. The diameter of each wheel is calibrated to a controller so that the controller can calculate the wheel speed based on the rotational speed sensor. The hydraulic braking system includes at least one brake rotor mounted to the second axle and a caliper coupled to the chassis. The hydraulic braking system also includes a master cylinder operably coupled to a brake actuator, which actuates the master cylinder to generate a first stopping force applied to the brake rotor by the brake caliper. The brake actuator is connected to the controller. The hydraulic braking system also includes a pressure sensor connected to the controller, which sends a pressure signal to the controller of the first stopping force generated by the master cylinder within the hydraulic braking system. The second axle, brake caliper, and brake rotor are mounted at one end of the chassis, and the master cylinder and brake actuator are mounted at the opposite end of the chassis. The braking system includes a caliper for each rotor. The traverseable vehicle also includes a steering system, wherein the second axle is connected to the steering system such that the wheels mounted to the second axle are steerable wheels. At least one electric motor is further defined as two electric motors, with one electric motor connected to each of the first axles. The traversable vehicle also includes a drivetrain connecting the electric motors and the first axles. The drivetrain includes a suspension system comprising one or more shock absorbers. Motor parameters are defined as the rotational speed of the electric motor. Motor parameters are defined as the torque generated by the electric motor. Motor parameters are defined as two motor parameters, where the first parameter is the rotational speed of the electric motor and the second parameter is the torque generated by the electric motor. The chassis also includes a suspension system comprising one or more shock absorbers. The chassis is divided into at least two compartments, where the first compartment accommodates at least the first axle and the second compartment accommodates at least the second axle. The second compartment is the width of the chassis accommodating the steering system and steerable wheels. The second compartment is further divided such that each steerable wheel is located in a wheel chamber. The electric motor comprises two electric motors and the first shaft comprises two first shafts, each motor and the corresponding shaft including a drive system connecting the electric motor and the first shaft to form a first drive system and a second drive system; and wherein the first compartment is divided into at least two chambers, each chamber accommodating one of the first drive system and the second drive system. One or more batteries are located between the first compartment and the second compartment and in a third compartment between the first compartment and the second compartment.

[0012] One aspect of this application includes a method for controlling a test vehicle capable of being overtaken during high deceleration, wherein the test vehicle has at least one electric motor. The method further includes the steps of: determining a ground speed of the test vehicle; determining a rotational speed of an axle of the test vehicle; calculating a wheel slip threshold using a controller based on the ground speed and the axle speed; actuating a hydraulic braking system to apply a first braking force less than the wheel slip threshold; controlling one or more motor parameters of one or more electric motors using the controller to apply a second braking force and adjust the speed and torque to be less than the wheel slip threshold; and simultaneously applying the first and second braking forces to decelerate the test vehicle without wheel slip.

[0013] Some implementations may include one or more of the following features. In this method, the step of calculating the wheel slip threshold is further defined as calculating the difference between the rotational speed of the axle and the ground speed. The hydraulic braking system includes at least one brake rotor mounted to the axle and a clamp coupled to the chassis of a test vehicle that can be traversed, and a master cylinder operably coupled to a brake actuator connected to a controller. The hydraulic braking system also includes a pressure sensor connected to the controller, and the method further includes the step of sending a pressure signal from the pressure sensor to the controller of a first stopping force generated by the master cylinder within the hydraulic braking system. The method further includes the step of using the controller to change the actuation distance of the brake actuator and change the stopping force applied through the hydraulic braking system based on the pressure signal of the stopping force. Attached Figure Description

[0014] Figure 1 It is a perspective view of a test vehicle that can be traversed by a soft target that can be hit by the vehicle.

[0015] Figure 2 It is a perspective view of the test vehicle and soft target;

[0016] Figure 3A The test vehicle is shown to be consistent with the teachings of this article;

[0017] Figure 3B The test vehicle is shown to be consistent with the teachings of this article;

[0018] Figure 4 This is a perspective view of the test vehicle after the cover has been removed;

[0019] Figure 5A The front of the braking system located in the test vehicle is shown;

[0020] Figure 5B The front of the test vehicle without a frame is shown;

[0021] Figure 6 The front of the test vehicle is shown;

[0022] Figure 7 The front of the test vehicle is shown;

[0023] Figure 8 The front of the test vehicle is shown;

[0024] Figure 9 An example showing a portion of the rear drive mechanism and braking system;

[0025] Figure 10 This is a block diagram of the braking control system;

[0026] Figure 11 It is a graphical representation of slowing down an OTV using only a hydraulic braking system;

[0027] Figure 12 This is a graphical representation of how an OTV is slowed down using an anti-skid braking system, consistent with the teachings of this article.

[0028] Figure 13 and Figure 14 It is a graphical representation of the range of braking force commanded by the hydraulic braking system and the electric motor. Detailed Implementation

[0029] The explanations and descriptions presented herein are intended to familiarize others skilled in the art with their teachings, principles, and practical applications. Those skilled in the art can adapt and apply these teachings in various forms best suited to the requirements of a particular application. Therefore, the specific embodiments set forth herein are not intended to be exhaustive or limiting of this application. Consequently, the scope of this application should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For all purposes, the disclosure of all articles and references (including patent applications and publications) is incorporated herein by reference. Other combinations that may derive from the appended claims are also possible and are also incorporated herein by reference.

[0030] This application relates to a test vehicle for advanced collision avoidance technology. The test vehicle 10 can be used as a mobile and controllable platform to hold a simulated target object 92, such as a car, truck, pedestrian, bicycle, etc. The test vehicle can be a trespassable test vehicle (referred to herein as an OTV). During collision avoidance testing, the OTV may be subjected to severe conditions, including being knocked down by a vehicle 90 equipped with advanced collision avoidance technology.

[0031] The OTV 10 includes a chassis 12. The chassis 12 can serve as the base structure or frame of the test vehicle. The chassis can be made of steel, composite materials, plastics, or a combination thereof. The chassis may include multiple ramps 22 removably connected to the chassis 12. The chassis 12 may include a removable cover 20. The chassis 12 can be connected to multiple wheels 18, one or more suspension systems 40, a steering system 36, braking systems 50, 60, a controller 80, one or more receivers, one or more motors 10, one or more batteries 82, multiple sensors (e.g., 24, 56, 64), or combinations thereof.

[0032] The chassis 12 can be divided into separate compartments to house the different systems and components of the OTV 10. These compartments can be used to separate mechanical systems, electrical systems, power systems, sensors, wheels, braking systems, steering systems, or combinations thereof from each other. The compartments can be sealed or unsealed. The compartments can be watertight. The chassis 12 can include two or more, three or more, four or more, eight or more, or even ten or more compartments. For example, the chassis 12 can be divided into at least two compartments, where the first compartment houses at least the first axle, and the second compartment houses at least the second axle. The chassis 12 can be divided such that the steering system 36 connected to the front axle is the width of the chassis 12, and further divided to place each wheel 18 in a separate wheel chamber. One of the compartments of the chassis 12 can house one or more electric motors 24. In one example, the OTV 10 has two electric motors 24, each of which can be located in a separate chamber within the chassis.

[0033] The OTV 10 may include a cover 20. The cover 20 serves to protect the control system of the test vehicle 10. The cover 20 allows the vehicle 90 to pass over the top of the test vehicle 10. The cover 20 may be removably attached to the chassis 12 of the test vehicle 10. The cover 20 may include one or more through-holes for housing one or more batteries 82 in the test vehicle 10. The cover 20 may include one or more vents, one or more handles, one or more locks, or combinations thereof. The cover 20 may be made of steel, composite materials, plastic, or combinations thereof. The cover 20 may be made of the same material as the frame 12, ramp 22, or both. The cover 20 may be made of a different material than the frame 12, ramp 22, or both. The cover may be on the same plane as the tops of the multiple ramps 22.

[0034] The OTV 10 includes one or more batteries 82. The one or more batteries 82 can provide power to the test carrier 10. The test carrier 10 may have one or more, two or more, three or more, four or more, or even more batteries. The one or more batteries 82 can be removably connected to the test carrier 10. The one or more batteries may be located in one or more compartments of the OTV 10. When installed in the test carrier, the one or more batteries 82 may be flush with the top surface of the cover 20 of the test carrier 10.

[0035] The OTV 10 may include multiple ramps 22. The chassis 12 may be connected to the multiple ramps 22. The multiple ramps 22 may assist the vehicle 90 with Advanced Driver Assistance Systems (ADAS) technology in knocking down the vehicle 10 by allowing the tires of the vehicle 90 to climb over it. The chassis 12 may include one or more, two or more, three or more, four or more, six or more, eight or more, ten or more ramps 22. The ramps 22 may be permanently connected to the chassis 12. The ramps 22 may be removably connected to the chassis 12. The tops of the multiple ramps 22 may be flush with the chassis cover 20. The test vehicle 10 may include at least one ramp 22 on each side or section of the test vehicle 10, allowing the test vehicle to easily overtake on either side.

[0036] One of the multiple sensors located in the OTV 10 may include a ground speed sensor. The ground speed sensor can be used to calculate the speed of the chassis 12. The ground speed sensor can be connected to the controller 80 and send speed measurements, inertial measurements, or both to the controller 80 for processing. The ground speed sensor can be located on or within the controller 80. The ground speed sensor 80 may further be supported by GPS to determine the ground speed of the chassis 12.

[0037] The OTV 10 includes a steering system 36. The steering system 36 serves to guide the movement of the OTV 10. The steering system 36 may include one or more steering shafts 38, one or more steering knuckles, one or more steering actuators, or combinations thereof. The steering system 36 may be connected to one or more wheels 18, one or more suspension systems (e.g., 40), one or more motors 24, or combinations thereof. In one example, the steering system 36 is located in the front 14 of the chassis 12 and connects the right and left front wheels to the steering shaft 38, which is operatively coupled to a steering actuator so that when a signal is given to the steering actuator, the left and right wheels move in concert to turn the OTV 10.

[0038] The chassis 12 is connected to one or more suspension systems 40. The suspension systems 40 can provide damping to the OTV 10. The suspension systems 40 can absorb some of the impacts from being knocked over during testing, thereby minimizing damage to the OTV 10. The suspension systems 40 may include one or more shock absorbers and / or dampers. The one or more shock absorbers may be vibrating elements, struts, springs, or any other suitable damping device. The one or more suspension systems 40 can be operatively connected to one or more wheels 18, one or more axles 28, one or more motors 24, one or more steering systems 36, or combinations thereof. For example, a first damper is connected to a first drive axle assembly, and a second damper is connected to a second drive axle assembly, so that the drive wheels remain mounted on the drive surface as the OTV traverses changes in the driving surface. In another example, the suspension system 40 absorbs a large amount of impact from the vehicle 90 passing over the test vehicle 10.

[0039] The OTV 10 includes one or more motors 24 connected to the chassis 12. The one or more motors 24 can provide propulsion to the OTV 10. The one or more motors can assist in slowing or stopping the OTV 10. The one or more motors 24 can be electric motors. The OTV 10 may include one or more, two or more, three or more, four or more, or more motors 24. Each motor 24 may include a motor housing and an output shaft. The one or more motors 24 may be part of braking systems 50, 60. The one or more motors 24 may be connected to a steering system 36, a suspension system 40, one or more power sources 82, one or more wheels 18, one or more chain drives 26, or combinations thereof. In one example, the OTV 10 includes two motors 24 positioned on the rear 16 of the chassis 12, with one motor 24 connected to each rear wheel 18, such that each rear wheel of the OTV 10 is independently powered.

[0040] One or more motors 24 can be controlled by one or more motor parameters. Motor parameters are one or more outputs of the motor, which can be commanded by the controller 80. Motor parameters may include motor speed, motor torque, or both. One or more motor parameters can be executed by transmitting a specific current to one or more motors 24. For example, when the controller 80 commands deceleration, one or more motors 24 can receive the commanded current, thereby slowing down the OTV 10 at a desired rate by adjusting the motor speed, motor torque, or both.

[0041] The OTV 10 includes a plurality of wheels 18. These wheels serve to move the OTV 10 across a surface. The chassis 12 may include two or more, three or more, four or more, six or more, eight or more, or ten or more wheels 18. For example, the chassis 12 may accommodate four wheels 18, with two in a forward position 14 and two in a rearward position 16. Preferably, each wheel 18 is cylindrical. Each of the plurality of wheels 18 may be connected to one or more motors 24, one or more suspension systems 40, one or more steering systems 36, one or more braking systems 50, 60, one or more drive axles 28, one or more brake axles 54, one or more speed sensors 56, at least one tire, or a combination thereof.

[0042] One or more motors 24 are connected to one or more wheels 18 via a drive train 26. The drive train 26 may be a chain drive. The chain drive 26 serves to transmit rotational motion from the output shaft of the motor 24 to power the wheels 18. Each motor 24 may include one or more, two or more, three or more, or more chain drives 26. Each chain drive 26 may include a first sprocket 30 on the output shaft of the motor 24 and a second sprocket 32 ​​on the drive shaft 28 of the wheel 18. Each chain drive 26 may include at least one transmission device between the first sprocket 30 and the second sprocket 32. For example, a chain drive may include at least one chain 34. In another example, a chain drive 26 may include at least one belt.

[0043] Each of the plurality of wheels 18 may include a tire wound around its circumference. The tire serves to provide traction on a surface. The tire may be made of natural rubber, synthetic rubber, plastic, fabric, steel, polymer, or a combination thereof. The tire may be inflatable. The tire may be solid. The tire may be a disposable item that can be replaced when worn.

[0044] The test vehicle 10 includes braking systems 50 and 60. Braking systems 50 and 60 can slow down or stop the OTV 10. Braking systems 50 and 60 may include one or more brake rotors 52, one or more brake clamps 58, one or more master cylinders 66 operably connected to an actuator 68, one or more lines 62 connecting the one or more master cylinders 66 to the one or more brake clamps 58, a pressure sensor 64 in fluid communication with the one or more brake lines 62, one or more motors 24, or combinations thereof. Braking systems 50 and 60 can be electronically actuated, mechanically actuated, electromechanically actuated, hydraulically actuated, or combinations thereof. For example, an electrical signal from the controller 80 can be received by the actuator 68 to depress the master cylinder 66 a certain distance, forcing hydraulic fluid through the brake line 62, through the hydraulic block 61, to the brake clamp 58, causing the brake clamp 58 to clamp the brake rotor 52, thereby slowing the rotational speed of the wheel 18. In another example, controller 80 can send electrical signals to one or more motors 24 to adjust motor speed (e.g., revolutions per minute (RPM) of the output shaft of an electric motor), adjust motor torque, or both, thereby slowing down or stopping OTV 10. In another example, braking systems 50, 60 can use controller 80 to actuate master cylinder 66 and adjust motor speed, torque, or both, thereby slowing down OTV 10 without causing wheel slippage.

[0045] Braking systems 50 and 60 include one or more brake rotors 52. The one or more brake rotors 52 can serve to receive forces applied by one or more brake clamps 58. Braking systems 50 and 60 may include one or more, two or more, three or more, four or more, six or more, or more brake rotors 52. The one or more brake rotors 52 can be connected to at least one of a plurality of wheels 18. The one or more brake rotors 52 can be directly or indirectly connected to at least one of the plurality of wheels 18. For example, a brake rotor 52 can be indirectly connected to at least one wheel 18 via a brake shaft 54. The one or more brake rotors 52 can be clamped by brake clamps 58. For example, when a clamping force is applied to the one or more brake rotors 52, the one or more brake rotors 52 can slow down the rotational speed of the brake shaft 54 ​​and the wheel 18 connected thereto.

[0046] One or more rotors 52 are connected to a brake axle 54. The brake axle 54 can serve to rotatably connect a wheel 18 to one or more brake rotors 52. The chassis 12 of the OTV 10 may include one or more, two or more, three or more, or more brake axles 54. Each brake axle 54 can connect one or more, two or more, three or more, four or more, or more brake rotors 52 to at least one wheel 18 of the OTV 10. For example, the OTV 10 may have one brake axle 54 and two brake rotors 52 connected to each of the front wheels 10, such that each wheel is rotatably connected to two brake rotors 52. Each brake axle 54 may include a rotational speed sensor 56 to sense the rotational speed of the brake axle 54 and the wheel 18.

[0047] The brake shaft 54 ​​may include a rotational speed sensor 56. The rotational speed sensor 56 can determine the rotational speed of the brake shaft 54 ​​and the connected wheel 18. The rotational speed sensor 56 can transmit the sensed rotational speed to the controller 80 for analysis.

[0048] Braking systems 50 and 60 include one or more brake clamps 58. The one or more brake clamps 58 can provide clamping force to one or more brake rotors 52 to reduce the rotational speed of multiple wheels 18. Each of the one or more brake rotors 52 has a corresponding brake clamp 58. Each of the one or more brake clamps 58 may include two brake pads. Braking systems 50 and 60 may include one or more, two or more, three or more, four or more, six or more, or more brake clamps 58. One or more brake clamps 58 can be fluidly connected to a master cylinder 66 via one or more brake lines 62.

[0049] Braking systems 50 and 60 include a master cylinder 66. The master cylinder 66 converts directional force into hydraulic pressure. The master cylinder 66 may include a piston and a bore. Braking systems 50 and 60 may include one or more, two or more, three or more, or four or more master cylinders 66. The master cylinder 66 may be fluidly coupled to a hydraulic fluid reservoir 72. The master cylinder 66 may be in fluid communication with one or more brake lines 62, a hydraulic distributor 61, a pressure sensor 64, one or more brake clamps 58, or combinations thereof. The master cylinder 66 may be actuated by an actuator 68. For example, the actuator 68 may depress the piston within the master cylinder, thereby generating hydraulic pressure to close one or more brake clamps 58.

[0050] Braking systems 50 and 60 include a brake actuator 68. The brake actuator 68 engages the master cylinder 66. The brake actuator 68 can be directly connected to the master cylinder 66. The brake actuator 68 can be connected to the master cylinder 66 via a connecting rod 70. The brake actuator 68 can be a mechanical actuator, an electric actuator, an electromechanical actuator, or a combination thereof. For example, the brake actuator 68 is a linear electric actuator that receives electrical signals from a controller 80, a pressure sensor 64, or both, to engage the master cylinder 66 by a calculated distance. Alternatively, the brake actuator can be controlled by a required pressure, not just a stroke. The linear electric actuator 68 moves the piston of the master cylinder 66 a specific calculated distance, thereby generating a predetermined amount of hydraulic pressure. The hydraulic pressure is converted into a specific clamping force applied to one or more brake clamps 58 by one or more brake rotors 52.

[0051] Braking systems 50 and 60 include a hydraulic distributor 61. The hydraulic distributor 61 functions to distribute hydraulic fluid to two or more locations. For example, a master cylinder 66 is connected to the input of the distributor 61, and two brake lines 62 are connected to the outlet side of the distributor, so that when the master cylinder 66 is actuated, hydraulic pressure is evenly distributed through the two brake lines 62. The hydraulic distributor 61 may include one or more, two or more, three or more, four or more, or more inlets. The hydraulic distributor 61 may include two or more, three or more, four or more, or more outlets. Two or more outlets may be connected to one or more brake lines 62, one or more pressure sensors 64, or a combination thereof.

[0052] The braking system may include one or more pressure sensors 64. The one or more pressure sensors 64 may monitor the amount of hydraulic pressure applied by the master cylinder 66. The one or more pressure sensors 64 may further transmit the hydraulic pressure values ​​in the braking systems 50 and 60 to the controller 80.

[0053] Braking systems 50 and 60 include a controller 80. The controller 80 controls the amount of braking force applied to the wheels 18 of the OTV 10. The controller 80 can receive data from multiple sensors (e.g., a ground speed sensor, a rotational speed sensor 56, a pressure sensor 64, and a motor 24). The controller 80 can calculate a wheel slip threshold based on the data received from the multiple sensors. The controller 80 can look up the optimal amount of wheel torque that can be applied by the braking systems 50 and 60 based on the sensor data in a database or library. The controller 80 may include algorithms to optimize braking without causing wheel slippage. The controller 80 can send commands to the brake actuator 68, one or more motors 24, or both, to slow the OTV without causing wheel slippage. The controller 80 can distribute braking force among the braking systems 50 and 60 and one or more motors 24 to optimize braking performance.

[0054] In one example, the OTV 10 can travel at a test speed. The controller 80 receives data from multiple sensors, such as one or more rotational speed sensors 56 and at least one ground speed sensor. The controller 80 calculates the standard deviation between the wheel rotational speed (combined with pre-calibrated wheel and tire diameters) and the chassis speed (ground speed) to determine the wheel slip threshold. Once the controller 80 has calculated the wheel slip threshold based on the pre-calibrated wheel height, wheel rotational speed, and chassis ground speed, it can look up the corresponding actuator value in a database. The actuator value can be a specific movement distance that will generate a specific amount of hydraulic pressure when the master cylinder 66 moves. The controller 80 then sends the actuator value to the brake actuator 68. The brake actuator 68 receives the value from the controller 80 and moves the master cylinder 66 a specific distance, thereby generating optimal braking force relative to the wheel slip threshold through the hydraulic braking systems 50 and 60. The optimal force, as clamping pressure (determined by the actuator 68 through the calculated travel distance of the master cylinder 66), is applied by one or more brake clamps 58 to one or more brake rotors 52 to slow down the OTV 10 without causing wheel slippage.

[0055] In another example, in addition to wheel speeds from one or more rotational speed sensors 56 and ground speeds from at least one ground speed sensor, controller 80 also receives one or more motor parameters from one or more motors 24. Controller 80 analyzes the motor parameters, wheel rotational speeds, and ground speeds, and then calculates the standard deviation between the wheel rotational speeds and chassis speeds to determine a wheel slip threshold. Once controller 80 has calculated the wheel slip threshold based on pre-calibrated wheel height and / or wheel circumference, wheel 18 rotational speeds, chassis ground speeds, and one or more electric motor parameters, controller 80 can determine the corresponding actuator values ​​and corresponding motor parameters for optimal braking. The actuator value can be a specific travel distance that will generate a specific amount of hydraulic pressure when the master cylinder 66 moves, thereby generating a first braking force. The motor parameter value can be a specific motor speed or torque that motor 24 applies to slow down OTV 10, thereby inducing a second braking force. The hydraulic braking system and the electric motors work together to slow down or stop the OTV without inducing wheel slip. The controller 80 simultaneously sends actuator values ​​to the brake actuator 68 and commands corresponding motor parameters from one or more motors 24. The brake actuator 68 receives the values ​​from the controller 80 and moves the master cylinder 66 a specific distance, thereby applying a calculated force as clamping pressure to one or more brake rotors 52 via one or more brake clamps 58, and the one or more motors 24 adjust the motor output (e.g., torque, rotational speed, or both) to generate optimal braking force relative to the wheel slip threshold, which allows the OTV 10 to decelerate optimally without causing wheel slippage.

[0056] Figure 1 This is a perspective view of OTV 10 during the test, showing the target object 92 being impacted by the carrier 90.

[0057] Figure 2 This is a perspective view of the OTV 10, which maintains the shape of a pedestrian-like target object 92. The OTV is shown as having a cover 20 and a ramp 22.

[0058] Figure 3A and Figure 3B This is a perspective view of the OTV 10, consistent with the teachings of this document. The OTV is shown as having a cover 20 and a ramp 22. The battery 82 is housed within the chassis via the cover 20.

[0059] Figure 4This is a perspective view of OTV 10. The OTV includes a frame 12 with wheels 18. The OTV has a front section 14 and a rear section 16. Viewed from the front section 14, OTV 10 includes a steering system 36 connected to the wheels 18 via a steering shaft 38. The wheels 18 are connected to a damper 40 and a brake shaft 54. The brake shaft 54 ​​is coupled to a brake rotor 52 and a rotational speed sensor 56. When the OTV 10 issues a deceleration or stop signal, the clamp 58 engages with the brake rotor 52. Moving to the rear section 16, a motor 24 is connected to the wheels 18 via a chain drive 26. The chain drive 26 includes a first sprocket 30 on the output of the motor 24 and a second sprocket 32 ​​connected to the drive shaft 28. The drive shaft 28 is connected to the wheels 18. The rear section of the brake assembly 60 includes a master cylinder 66 fluidly connected to a fluid reservoir 72 and a distribution block 61 via a brake line 62. A pressure sensor 64 is located in the distribution block 61. The main control cylinder 66 is connected to the electric brake actuator 68 via the actuator rod 70. When the brake actuator 68 is working, the main control cylinder 66 converts linear motion into hydraulic pressure, which is used to close the brake clamp 58 onto the brake rotor 52.

[0060] Figure 5A and Figure 5B The front portion 14 of the OTV 10 is shown, which includes the front of the steering system 36 and the braking system 50. (See diagram) Figure 1 As shown, the steering system 36 is connected to the wheel 18 via a steering shaft 38. The wheel 18 is further connected to a damper 40 and a brake shaft 54. The brake shaft 54 ​​is coupled to a brake rotor 52, so when the brake clamp 58 receives hydraulic pressure generated by the master cylinder 66, the brake clamp 58 clamps onto the brake rotor 52, thereby reducing the rotational speed of the brake shaft 54 ​​and the wheel 18. A rotational speed sensor 56 straddles the brake shaft 54 ​​and reports the rotational speed of the brake shaft 54 ​​and the wheel 18 to the controller 80. The controller 80 processes the information from the rotational speed sensor 56 and ground speed data from a ground speed sensor (not shown) to calculate the standard deviation between the rotational speed of the wheel 18 and the speed of the chassis 12 (e.g., wheel slippage). Once the controller 80 determines the wheel slippage threshold, the controller 80 sends a signal to the brake actuator 68 to move the master cylinder 66 a specific distance, thereby generating corresponding hydraulic pressure. Hydraulic pressure is delivered via brake line 62 through distribution block 61 to brake clamp 58, which converts the hydraulic pressure into clamping force on brake rotor 52, thereby slowing down the rotational motion of brake shaft 54 ​​and wheel 18 without causing wheel slippage.

[0061] Figure 6 , Figure 7 and Figure 8An example of the front portion of the steering system 36 and braking system 50 is shown. The front portion of the braking system 50 includes a brake clamp 58, a brake rotor 52, and a brake shaft 54. The front portion of the braking system 50 is separated from the rear portion of the braking system 60, which includes hydraulically actuated components (e.g., a master cylinder 66, a distribution block 61, and a brake actuator 68) encapsulated to allow the OTV to maintain its ultra-low profile while retaining sufficient performance.

[0062] Figure 9 The rear section 16 of the OTV 10 is shown, which includes a rear drive mechanism (motor 24, chain drive 26) and a portion of a braking system 60 (e.g., master cylinder 66, distribution block 61, brake actuator 68). The motor 24 is connected to the wheels 18 via the chain drive 26. The chain drive 26 includes a first sprocket 30 at the output of the motor 24 and a second sprocket 32 ​​connected to a drive shaft 28. The drive shaft 28 is connected to the wheels 18. The motor 24 is also in communication with a controller 80. The controller 80 sends and receives information about the motors 24 and adjusts the output of each motor 24 (e.g., motor RPM) according to conditions.

[0063] Figure 10 A block diagram of the control system is shown, illustrating an example process for controlling the braking of an OTV. Ground speed and rotational speed sensors feed data to the controller. The controller processes the ground speed of the OTV, the rotational speed of at least one axle, and the tire circumference to calculate a wheel slip threshold. Once the wheel slip threshold is calculated, the controller then determines if there is a high amount of slip or a high rate of change of wheel slip. If no high amount of slip or high rate of change of wheel slip is found, the controller continues monitoring until a wheel slip condition occurs. Once a wheel slip condition is identified, the controller analyzes the currently commanded braking pressure and compares it to a target hydraulic pressure below the wheel slip threshold. The controller then sends a command signal to the hydraulic braking system to adjust the braking pressure to the desired level. While the controller is calculating the target braking pressure and sending it to the hydraulic braking system, it is also monitoring and controlling one or more electric motors. The controller analyzes the motor parameters of the electric motors and calculates a target current (target motor output) to adjust one or more motor parameters below the wheel slip threshold. The controller then sends the target current to the one or more electric motors. The hydraulic braking system and the electric motors simultaneously apply the target hydraulic pressure and target current, thereby decelerating the OTV without allowing the wheels to slip.

[0064] Figure 11An example of an OTV stopping without an anti-skid braking system consistent with the teachings of this article is shown. The graph shows the wheel rotations (revolutions per minute) affected by applied braking force. The curve shows a sharp drop in wheel rotations, indicating that the wheels are locked and slipping when using only the hydraulic braking system. The graph gives the expected rotations under deceleration conditions so that the OTV can maintain control and not enter a wheel slip condition.

[0065] Figure 12 A graphical representation of anti-slip braking, which utilizes both a hydraulic braking system and an electric motor to decelerate an OTV, is shown. Figure 11 compared to, Figure 12 The curve did not drop sharply, indicating that there was no wheel slippage when the hydraulic braking system and one or more electric motors were used to stop the OTV. Instead, the OTV decelerated from high speed to 0 in a relatively linear manner.

[0066] Figure 13 and Figure 14 The target braking force of the hydraulic braking system and the electric motor are shown respectively. Figure 13 An example of a target braking pressure range applied in bars is shown, which is used to generate a target stopping force for a hydraulic braking system to prevent wheel slippage when slowing down an OTV. Figure 14 An example of a target current range applied in amperes is shown, used to generate a target braking force for the electric motor to prevent wheel slippage during OTV deceleration. The target braking forces generated by the hydraulic braking system and the electric motor work together to rapidly decelerate the OTV without causing wheel slippage or wheel spin during rapid deceleration. Controller 80 calculates the ideal ratio between front and rear braking forces based on the OTV's center of gravity and mass. In one example, the front braking force is generated by hydraulic braking systems 50, 60, while the rear braking force is generated by electric motor 24. Controller 80 calculates a first braking force and a second braking force generated by hydraulic braking systems 50, 60 and electric motor 24, respectively, thereby altering the vertical tire force during deceleration (e.g., the front vertical tire force increases and the rear vertical tire force decreases with increasing deceleration). The controller calculates the optimal amount of force that the front braking systems 50, 60 and rear braking system 24 must apply while balancing the vertical tire forces between the front and rear wheels.

Claims

1. A traversable test carrier comprising an electronically controlled anti-skid braking system for reducing wheel slip during rapid deceleration, the traversable test carrier comprising: a chassis; at least two wheels rotatably coupled to the chassis; at least one electric motor operably coupled with the at least two wheels; a hydraulic braking system partially supported by the chassis and operably coupled with the at least two wheels; a rotational speed sensor connected to the at least two wheels for determining a rotational speed of the at least two wheels; a ground speed sensor supported by the chassis for determining a ground speed of the chassis; and a controller operably connected with the at least one electric motor, the hydraulic braking system, the rotational speed sensor, and the ground speed sensor, the controller configured to: calculate a difference between the rotational speed of the at least two wheels and the ground speed of the chassis to determine a slip threshold of the wheels; actuate the hydraulic braking system to apply a first arresting force; control at least one motor parameter of the at least one electric motor to apply a second arresting force; wherein the first arresting force and the second arresting force combined are less than the slip threshold of the wheels to cause the chassis to rapidly decelerate without wheel slip conditions.

2. The traversable test carrier of claim 1, wherein a diameter of each wheel is calibrated into the controller so that the controller can calculate wheel speed based on the rotational speed sensor.

3. The traversable test carrier of claim 1, wherein the hydraulic braking system comprises at least one brake rotor, a clamp, and a master cylinder operably coupled with a brake actuator, wherein the brake actuator actuates the master cylinder to generate the first arresting force applied by the brake clamp to the brake rotor, and wherein the hydraulic braking system further comprises a pressure sensor connected to the controller, wherein the pressure sensor sends a pressure signal of the first arresting force generated by the master cylinder within the hydraulic braking system to the controller.

4. The traversable test carrier of claim 1, wherein the at least one electric motor is further defined as two electric motors.

5. The traversable test carrier of claim 1, wherein the motor parameter is defined as a rotational speed of a spin of the electric motor.

6. The traversable test carrier of claim 1, wherein the motor parameter is defined as a torque generated by the electric motor.

7. A traversable test carrier comprising an electronically controlled anti-skid braking system for reducing wheel slip during rapid deceleration, the traversable test carrier comprising: a chassis; at least two wheels rotatably coupled to the chassis; a first braking system operably coupled with the at least two wheels; a second braking system operably coupled with the at least two wheels; ​ a rotational speed sensor connected to the at least two wheels for determining a rotational speed of the at least two wheels; a ground speed sensor supported by the chassis for determining a ground speed of the chassis; and a controller operably connected to the first braking system, the second braking system, the rotational speed sensor, and the ground speed sensor, the controller configured to: calculate a difference between the rotational speed of the at least two wheels and the ground speed of the chassis to determine a slip threshold of the wheels; control at least one parameter of the first braking system to apply a first arresting force; control at least one parameter of the second braking system to apply a second arresting force; wherein the first arresting force and the second arresting force combined are less than the slip threshold of the wheels to cause the chassis to decelerate without wheel slip conditions.

8. The traversable test carrier of claim 7, wherein a diameter of each wheel is calibrated into the controller so that the controller can calculate wheel speed based on the rotational speed sensor.

9. The traversable test carrier of claim 7, wherein calculating the wheel slip threshold is further defined as calculating a difference between the rotational speed of the wheels and the ground speed.

10. The traversable test carrier of claim 7, wherein one of the first braking system and the second braking system is a hydraulic braking system, the hydraulic braking system including at least one brake rotor mounted to a shaft by a clamp attached to a chassis of the traversable test carrier and a master cylinder operably coupled to a brake actuator, wherein the brake actuator is connected to the controller, and the hydraulic braking system further includes a pressure sensor connected to the controller.

11. The traversable test carrier of claim 7, wherein one of the first braking system and the second braking system includes one or more electric motors configured to apply an arresting force to cause the traversable test carrier to decelerate without wheel slip conditions. ​

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