【正文】 in the . While DIRAVI is not the mechanical template for all modern power steering arrangements, it did innovate the now mon benefit of speed adjustable steering. The force of the centering device increases as the car39。 in the UK and 39。n SM in 1970, and was known as 39。s high pressure hydraulic system and is always the same no matter what the road speed is. As the steering wheel is turned, the wheels are turned simultaneously to a corresponding angle by a hydraulic piston. In order to give some artificial steering feel, there is a separate hydraulically operated system that tries to turn the steering wheel back to centre position. The amount of pressure applied is proportional to road speed, so that at low speeds the steering is very light, and at high speeds it is very difficult to move more than a small amount from the centre position. As long as there is pressure in the car39。s speed increases (this is known as variable assist power steering). DIRAVI In the DIRAVI system invented by Citro235。s output back to the hydraulic reservoir at high engine speeds. A pressure relief valve is also used to prevent a dangerous buildup of pressure when the hydraulic cylinder39。 the bottom end will not rotate as far as the top end. The difference in rotation between the top and bottom ends of the torsion bar can be used to control the valve that allows fluid to flow to the cylinder which provides steering assistance。s engine. A doubleacting hydraulic cylinder applies a force to the steering gear, which in turn applies a torque to the steering axis of the roadwheels. The flow to the cylinder is controlled by valves operated by the steering wheel。 } } 黑龍江工程學(xué)院本科生畢業(yè)設(shè)計(jì) 27 附錄 B History The earliest known patent related to power steering was that by Frederick W. Lanchester in the UK,in February 1902. His invention was to cause the steering mechanism to be actuated by hydraulic power. The next design was filed as recorded by the US Patent Office on August 30, 1932, by Klara Gailis, from Belmont, Massachusetts. There is another inventor credited with the invention of power steering by the name of Charles F. Hammond an American, born in Detroit, who filed similar patents, the first of which was filed as recorded by the Canadian Intellectual Property Office. Chrysler Corporation introduced the first mercially available power steering system on the 1951 Chrysler Imperial under the name Hydraguide. Most new vehicles now have power steering, owing to the trends toward front wheel drive, greater vehicle mass, and wider tires, which all increase the required steering effort. Heavier vehicles as mon in some countries would be extremely difficult to maneuver at low speeds, while vehicles of lighter weight may not need power assisted steering at all Hydraulic systems A power steering fluid reservoir and pulley driven pump Most power steering systems work by using a hydraulic system to turn the vehicle39。 delay_ms(50)。 m1=0。 m2=1。 delay_ms(50)。 黑龍江工程學(xué)院本科生畢業(yè)設(shè)計(jì) 26 m1=0。 m2=0。(temp255))) { n=15。(temp0))||((temp235)amp。 } if(((temp25)amp。amp。amp。(temp210))) { n=7。(temp50))||((temp185)amp。 } if(((temp75)amp。amp。amp。(temp160))) { n=1。(temp100))||((temp145)amp。 if(((temp115)amp。 while(1) 黑龍江工程學(xué)院本科生畢業(yè)設(shè)計(jì) 25 { temp = AD_Change()。 m1=1。 } void main(void) { uint a=30,temp=0,temp1=0。i48。t0。 } void delay_ms(uchar t) //延時(shí)函數(shù)，大概為 t 為 1，則延時(shí)5 到 6ms { uint i。 } temp = Average(Date_Buffer)。 //延時(shí) 1 毫秒采集一次。 i++) { Date_Buffer[i] = AD_Change1()。 for(i=0。 } /*********************************************************************** 黑龍江工程學(xué)院本科生畢業(yè)設(shè)計(jì) 24 * 名 稱 : AD_Filter() * 功 能 : 進(jìn)行 AD 采集 20 次，并進(jìn)行濾波處理 * 輸 入 : 二十次 AD 采集值 * 輸 出：經(jīng)過處理后的 AD 值 ***********************************************************************/ uint AD_Filter1() { uint Date_Buffer[20] = {0}, temp。 } temp = (uint)(((float)temp) / 10 + )。 i15。 } } ////對數(shù)組進(jìn)行處理，去掉一個(gè)最大值和一個(gè)最小值，中間的十個(gè)值再來求平均值 temp = 0。 buffer[j1] = buffer[j]。 j=i。 i20。 uint temp。 return temp。 if(AD_Out1 == 1) temp += 1。 黑龍江工程學(xué)院本科生畢業(yè)設(shè)計(jì) 23 _nop_()。 AD_In1 = 0。 _nop_()。 i8。 if(AD_Out1 == 1) temp += 1。 _nop_()。 _nop_()。 _nop_()。 AD_In1 = 0。 return(temp)。這里可以根據(jù)工作需要調(diào)整時(shí)間。 Delay(1)。 i20。 uchar i。 return(temp)。 i++) { temp += buffer[i]。 for(i=5。 buffer[j] = temp。 j) { if(buffer[j1] buffer[j]) { temp = buffer[j1]。 i++) ////先對整個(gè)數(shù)組的二十個(gè)值進(jìn)行從小到大的排列 for(j=19。 for(i=1。 } /*********************************************************************** * 名 稱 : Average() * 功 能 : 中位值平均濾波法，取一共二十個(gè)數(shù)據(jù)，最大和最小的五個(gè)數(shù)據(jù)不要 對中間的十個(gè)數(shù)據(jù)求平均值 * 輸 入 : 二十個(gè)待處理的值 * 輸 出：得到一個(gè)中位的平均值 ***********************************************************************/ uint Average(uint buffer[20]) { uchar i,j。 } } CS = 1。 if(i != 7) { temp = temp 1。 _nop_()。 _nop_()。 i++) { AD_In = 1。 for(i=0。 _nop_()。 _nop_()。 CS = 0。 _nop_()。 } /******************************************************************** * 名稱 : AD_Change(void) * 功能 : * 輸入 : 無 * 輸出 : temp （電壓值） ***********************************************************************/ uchar AD_Change(void) { uchar i,temp = 0。 j=148。 idel。 } /******************************************************************** * 名稱 : Delay() * 功能 : 延時(shí) ,延時(shí)時(shí)間為 1ms * del * 輸入 : del * 輸出 : 無 ***********************************************************************/ void Delay(uint del) { uchar i, j。 j=2。 i=10。 * 輸入 : 無 * 輸出 : 無 ***********************************************************************/ void delay() {