# US 11,906,392 B2 · In-vehicle stable platform system employing active suspension and control method thereof

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- Number: US 11,906,392 B2
- Document ID: US11906392B2
- Status: Granted
- Kind: B2
- Application number: 16/980,002
- Filed: 2019-08-01
- Published: 2021-01-14
- Granted: 2024-02-20
- Earliest claimed: 2018-09-10
- Assignees: Yanshan University
- Applicants: Yanshan University
- Inventors: Dingxuan Zhao; Mingde Gong; Shuang Liu; Zhiguo Sun; Zhuxin Zhang; Bin Yang; Tao Ni; Qinghe Guo; Mengke Yang
- Web page: https://patentgrep.com/patent/US11906392B2

## CPC

- B60G 17/0165: to an external condition, e.g. rough road surface, side wind
- G01M 17/04: Suspension or damping
- B60G 17/0152: {characterised by the action on a particular type of suspension unit (B60G17/01941 takes precedence)}
- B60G 17/0161: {mainly during straight-line motion (B60G17/0164 takes precedence)}
- B60G 17/0162: {mainly during a motion involving steering operation, e.g. cornering, overtaking (B60G17/0164 takes precedence)}
- B60G 17/018: characterised by the use of a specific signal treatment or control method
- B60G 17/0195: characterised by the regulation being combined with other vehicle control systems {(conjoint control of vehicle sub-units including control of suspension systems B60W10/22)}
- B60G 21/08: characterised by use of gyroscopes (gyroscopes for stabilising vehicle bodies without controlling suspension arrangements B62D37/06)
- B60G 17/00: Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load {(levelling or stabilising systems for tippers B60P1/045)}
- B60G 17/015: the regulating means comprising electric or electronic elements ({B60G17/002}, B60G17/005 take precedence)
- B60G 2202/40: Type of actuator
- B60G 2202/413: Hydraulic actuator
- B60G 2204/62: Adjustable continuously, e.g. during driving
- B60G 2300/122: Trikes
- B60G 2400/0511: Roll angle
- B60G 2400/0512: Pitch angle
- B60G 2400/102: vertical
- B60G 2400/252: vertical
- B60G 2401/28: Gyroscopes
- B60G 2500/30: Height or ground clearance
- B60G 2600/09: Feedback signal
- B60G 2600/182: Active control means
- B60G 2600/44: Vibration noise suppression
- B60G 2600/602: high pass
- B60G 2800/01: Attitude or posture control
- B60G 2800/012: Rolling condition
- B60G 2800/014: Pitch; Nose dive
- B60G 2800/0192: longitudinal with regard to vehicle
- B60G 2800/0194: transversal with regard to vehicle
- B62D 61/06: with only three wheels
- B60G: VEHICLE SUSPENSION ARRANGEMENTS (air-cushion vehicles B60V; {cycle suspensions B62K25/00})
- G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)

## Abstract

An in-vehicle stable platform system employing active suspension and a control method thereof is provided. The system includes a vehicle body, an in-vehicle stable platform, an inertial measurement device, an electronic control device, a servo controller set, multiple wheels, and suspension servo actuation cylinders and displacement sensors respectively corresponding to the wheels. The wheels are divided into three groups, which form three support points. The heights of the three support points are controlled to control orientation of the vehicle body. An amount of extension/retraction of the suspension servo actuation cylinders required to cause the in-vehicle stable platform to return to a horizontal level is calculated according to a measured pitch angle and a roll angle of the in-vehicle stable platform, and when a vehicle travels on an uneven road, the extension/retraction of each suspension servo actuation cylinder is controlled to cause the in-vehicle stable platform to be horizontal.

## Claims

### Claim 1

A control method of an orientation of a vehicle employing active suspension, characterized in that the vehicle has three or more wheels, the wheels are divided into three groups, which constitute three support points for supporting a vehicle body; heights of the three support points are controlled to control an orientation of the vehicle body; each of the wheel groups has one wheel or multiple wheels therein, when the number of wheels in some wheel group is greater than one, upper chambers and lower chambers of all of the suspension servo actuation cylinders in the wheel group are respectively communicated, and the wheel group forms a support point for supporting the vehicle body, three wheel groups form three support points, so that the orientation of the vehicle body is controlled according to a principle that a plane is determined by three points;
wherein the vehicle comprises a vehicle body, an inertial measurement device, an electronic control device, a servo controller set, multiple wheels, suspension servo actuation cylinders and displacement sensors respectively corresponding to the wheels, wherein the wheels are connected to a lower part of the vehicle body via the suspension servo actuation cylinders, and the displacement sensor is used to measure strokes of the suspension servo actuation cylinders, the electronic control device and servo controller set are secured to the vehicle body, the electronic control device is in communication with the inertial measurement device and the servo controller set, and the servo controller set is in communication with the displacement sensor, the electronic control device reads an orientation parameter measured by the inertial measurement device, calculates an amount of extension/retraction of each of the suspension servo actuation cylinders required to cause the vehicle body to return to a horizontal level, and outputs it to servo controller set, thereby controlling the extension/retraction of each of the suspension servo actuation cylinders;
wherein when the wheel groups are formed, the structures of the wheels in each of the wheel groups and the suspension servo actuation cylinders corresponding thereto and the displacement sensors are the same, and a support point supporting the vehicle body in each of the wheel groups is a geometric center point of the support point of each of the suspension servo actuation cylinders in the group to the vehicle body, and the height of the support point is controlled by controlling the average amount of extension/retraction of each of the suspension servo actuation cylinders in the group.

### Claim 2 (depends on 1)

The control method of the orientation of the vehicle employing active suspension according to claim 1, characterized in that, the method comprises establishing a coordinate system OXYZ fixedly connected with the vehicle body, wherein a coordinate origin O is a centroid of wheel grounding points when the vehicle is horizontal, and an upward direction passing through the coordinate origin O and perpendicular to the plane where an in-vehicle stable platform is located is defined as a Z-axis positive direction, a forward direction of the vehicle is defined as a Y-axis positive direction, and a right direction when the vehicle moves forward is defined as an X-axis positive direction, a heaving displacement of the in-vehicle stable platform along the Z-axis is set as w, a rotation angle around the X-axis is set as a, and a rotation angle around the Y-axis is set as β; scanning periods are preset in the inertial measurement device, and the control method comprises the following steps:
in the first step, in each of the scanning periods, the inertial measurement device measures a pitch angle α0 and a roll angle β0 and outputs them to the electronic control device;
in the second step, the electronic control device performs a first-order low-pass filtering with a cutoff frequency fL on the pitch angle α0 and the roll angle βo, and a filtered pitch angle is αL, a filtered roll angle is βL, the first-order digital low-pass filtering adopts a following recursive algorithm:
yn=αxn+(1−a)yn-1
wherein, xn is a sampling value of α0 or β0 in the current scanning period, yn is a calculating value of α0 or β0 in the current scanning period, yn-1 is a calculating value of α0 or β0 in the previous scanning period, and a is a filter coefficient;
in the case that the cut-off frequency fL is determined, the calculation method of a is:
a=2πfLΔt
wherein Δt is the scanning period, an unit of which is s; fL is the cut-off frequency, an unit of which is Hz;
in the third step, according to the values of αL and βL obtained in the previous second step, the electronic control device takes w=0 and −αL and −βL as relative correction values of the orientation of the in-vehicle stable platform, calculates the target values of the amount of extension/retraction of the suspension servo actuation cylinders of the vehicle, and transmits the target values to the servo controller set to perform displacement servo control on the suspension servo actuation cylinders, so as to cause the in-vehicle stable platform to be horizontal during traveling; when the target values of the amount of the extension/retraction of the suspension servo actuation cylinders are calculated by an inverse kinematics algorithm of a vehicle suspension mechanism with the three support points; when the servo controller set performs displacement control on the suspension servo actuation cylinders, the extension/retraction of the suspension servo actuation cylinders is controlled according to target values of the stroke and the amount of the extension/retraction of the suspension servo actuation cylinder measured by the displacement sensor, so as to cause the in-vehicle stable platform to be horizontal during traveling.

### Claim 3

An in-vehicle stable platform employing active suspension for a six-wheeled vehicle, characterized in that, the in-vehicle stable platform comprises a vehicle body (13), an in-vehicle stable platform (14) fixedly connected with the vehicle body, an inertial measurement device (1), an electronic control device (11), a servo controller set (12), wheels (2.1, 2.2, 3.1, 3.2, 4.1, 4.2), suspension servo actuation cylinders (5.1, 5.2, 6.1, 6.2, 7.1, 7.2) corresponding to the wheels (2.1, 2.2, 3.1, 3.2, 4.1, 4.2) one by one, and corresponding displacement sensors (8.1, 8.2, 9.1, 9.2, 10.1, 10.2);
wherein the inertial measurement device (1) is secured to the in-vehicle stable platform (14), and wheels (2.1, 2.2, 3.1, 3.2, 4.1, 4.2) are connected to a lower part of the vehicle body via the suspension servo cylinders (5.1, 5.2, 6.1, 6.2, 7.1, 7.2) respectively; the displacement sensors (8.1, 8.2, 9.1, 9.2, 10.1, 10.2) are used to measure strokes of the suspension servo actuation cylinders (5.1, 5.2, 6.1, 6.2, 7.1, 7.2), respectively, the electronic control device (11) and the servo controller set (12) are secured to the vehicle body (13), the electronic control device (11) is in communication with the inertial measurement device (1) and the servo controller set (12), the servo controller set (12) is in communication with the displacement sensors (8.1, 8.2, 9.1, 9.2, 10.1, 10.2), and the servo controller set (12) receives the measurement signals of the displacement sensors, the electronic control device (11) reads the orientation parameters measured by the inertial measurement device (1), calculates an amount of extension/retraction of each of the suspension servo actuation cylinders (5.1, 5.2, 6.1, 6.2, 7.1, 7.2) required to cause the in-vehicle stable platform to return to a horizontal level, and outputs it to the servo controller set (12) to control the extension/retraction of each of the suspension servo actuation cylinders (5.1, 5.2, 6.1, 6.2, 7.1, 7.2), so as to cause the in-vehicle stable platform to be horizontal during traveling;
wherein the wheels are divided into three wheel groups, and each of the wheel groups includes two wheels close to one another, when groups are formed, the structure and size of the wheels in some wheel group and the suspension servo actuation cylinder and the displacement sensor are the same, in which the wheels (2.1 and 2.2) are a first group, the wheels (3.1 and 3.2) are a second group, and the wheels (4.1 and 4.2) are a third group; the suspension servo actuation cylinders are also divided into three groups, in which the suspension servo actuation cylinders (5.1 and 5.2) are a first group, the suspension servo actuation cylinders (6.1 and 6.2) are a second group, and the suspension servo actuation cylinders (7.1 and 7.2) are a third group; the displacement sensors are also divided into three groups, in which the displacement sensors (8.1 and 8.2) are a first group, the displacement sensors (9.1 and 9.2) are a second group, and the displacement sensors (10.1 and 10.2) are a third group; upper chambers of the suspension servo actuation cylinders (5.1 and 5.2) are connected via an upper chamber connecting pipeline (15.2), and lower chambers thereof are connected via a lower chamber connecting pipeline (15.1), so that the wheels in the first group form a first support point upper chambers of the suspension servo actuation cylinders (6.1 and 6.2) are connected via an upper chamber connecting pipeline (16.2), and lower chambers thereof are connected via a lower chamber connecting pipeline (16.1), so that the wheels in the second group form a second support point upper chambers of the suspension servo actuation cylinders (7.1 and 7.2) are connected via an upper chamber connecting pipeline (17.1), and lower chambers thereof are connected via a lower chamber connecting pipeline (17.2), so that the wheels in the third group form a third support point a height of each of the support point is controlled by controlling an average amount of extension/retraction of each of the suspension servo actuation cylinders in the group;
wherein the control method of the in-vehicle stable platform employing active suspension for a six-wheeled vehicle comprises in the first step, a coordinate system OXYZ is established and fixedly connected with the vehicle body, a coordinate origin O of the coordinate system is defined as a centroid of all wheel grounding points when the vehicle is horizontal, a positive direction of a Z-axis is an upward direction passing through the origin O and perpendicular to a plane where the in-vehicle stable platform is located; a positive direction of a Y-axis is a forward direction of the vehicle; a right direction when the vehicle moves forward is a positive direction of a X-axis, a heaving displacement of the in-vehicle stable platform along the Z-axis is defined as w, a rotation angle around the X-axis, i.e. a pitch angle is defined as α, and a rotation angle around the Y-axis, i.e. a roll angle is defined as β; in each of scanning periods, the inertial measurement device measures the pitch angle α0 and the roll angle β0 and outputs them to the electronic control device;
in the second step, the electronic control device performs a first-order low-pass filtering with a cutoff frequency fL on the pitch angle α0 and the roll angle β0, and a filtered pitch angle is set as αL, a filtered roll angle is set as βL,
in the third step, according to values of αL and βL obtained in the second step, w=0 and −αL and −βL, are taken as a relative correction value of an orientation of the in-vehicle stable platform, a target value of an average amount of extension/retraction of each of the suspension servo actuation cylinders in each of the wheel groups of the vehicle is calculated through an inverse kinematics algorithm of a vehicle suspension mechanism with three support points, and a target value is transmitted to the servo controller set to perform displacement servo control on the suspension servo actuation cylinders in the wheel groups, so as to cause the in-vehicle stable platform to be horizontal during traveling.