【摘要】：高速數(shù)控加工系統(tǒng)在現(xiàn)代制造業(yè)中占據(jù)至關(guān)重要的地位,進(jìn)給速度和加工精度是評價該系統(tǒng)性能的關(guān)鍵性指標(biāo)。在高速加工過程中,速度突變點(diǎn)的存在造成進(jìn)給速度和進(jìn)給方向急劇變化,嚴(yán)重影響加工精度。因此,前瞻插補(bǔ)技術(shù)被引入到數(shù)控系統(tǒng)中并得到了廣泛應(yīng)用,較好地解決了這個問題。為了在數(shù)控加工中預(yù)先發(fā)現(xiàn)速度突變點(diǎn)、平穩(wěn)經(jīng)過插補(bǔ)點(diǎn)和防止速度突變引起的機(jī)床振動,本文結(jié)合NURBS曲線插補(bǔ),提出了速度自適應(yīng)三次多項(xiàng)式前瞻插補(bǔ)算法,并且建立了該算法的通用模型。首先根據(jù)NURBS曲線的相關(guān)計(jì)算值,由曲線中插補(bǔ)點(diǎn)曲率的變化總結(jié)了速度突變點(diǎn)的判定標(biāo)準(zhǔn),確定了速度突變點(diǎn)的位置。接著根據(jù)速度突變點(diǎn)對加工曲線進(jìn)行分段處理,提出了基于弓高誤差和三次多項(xiàng)式加減速的突變點(diǎn)速度局部最優(yōu)解。然后通過分析突變點(diǎn)處速度的嵌套關(guān)系,給出了前瞻距離的有效計(jì)算方法。最后根據(jù)計(jì)算減速點(diǎn)位置的要求,在前瞻范圍內(nèi)進(jìn)行反向插補(bǔ),提出了進(jìn)給速度的實(shí)時優(yōu)化方案。本文通過兩種不同的軌跡曲線對提出的速度自適應(yīng)三次多項(xiàng)式前瞻插補(bǔ)算法進(jìn)行了仿真驗(yàn)證,并與基于S型加減速算法和傳統(tǒng)三次多項(xiàng)式加減速算法進(jìn)行了性能對比仿真,結(jié)果驗(yàn)證了該算法比S型加減速算法的運(yùn)行時間減少了1.62%,比傳統(tǒng)三次多項(xiàng)式加減速算法的最大弓高誤差減少了6.77‰。此外,本算法在潤金科技數(shù)控加工平臺中進(jìn)行了試用,其單次插補(bǔ)時間最大為0.261ms,完全滿足該系統(tǒng)設(shè)定最大插補(bǔ)時間1ms的要求。
[Abstract]:High-speed NC machining system plays an important role in modern manufacturing industry. Feed speed and machining precision are the key indexes to evaluate the performance of the system. In the process of high speed machining, the existence of the sudden change of speed caused the sharp change of feed speed and feed direction, which seriously affected the machining accuracy. Therefore, the forward-looking interpolation technology is introduced into the CNC system and widely used to solve this problem. In order to detect the mutation point in advance, pass through the interpolation point smoothly and prevent the vibration of the machine tool caused by the sudden change of speed in NC machining, this paper presents an algorithm of speed adaptive cubic polynomial forward interpolation combined with NURBS curve interpolation. A general model of the algorithm is established. First, according to the relative calculation value of NURBS curve, the determination standard of velocity catastrophe point is summarized from the curvature change of interpolation point in the curve, and the position of velocity catastrophe point is determined. Then the processing curve is segmented according to the velocity catastrophe point, and the local optimal solution of the abrupt point velocity is proposed based on the error of arch height and the acceleration and deceleration of cubic polynomial. Then, by analyzing the nested relation of the velocity at the sudden change point, the effective calculation method of the forward distance is given. Finally, according to the requirement of calculating the position of deceleration point, reverse interpolation is carried out in the forward range, and the real-time optimization scheme of feed speed is put forward. In this paper, two different trajectory curves are used to verify the proposed algorithm, and the performance of the proposed algorithm is compared with that based on S-type acceleration and deceleration algorithm and traditional cubic polynomial acceleration and deceleration algorithm. The results show that the running time of this algorithm is 1.62 less than that of S-type acceleration and deceleration algorithm, and the maximum bow height error of the traditional cubic polynomial acceleration and deceleration algorithm is 6.77 鈥，

本文編號：2217769