Patent ID: 11906392
Assignee: YANSHAN UNIVERSITY
Field: Transport (Mechanical engineering)
Classification: CPC B  G | IPC B  G

Claim 1:
2. 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.