Another method would be to use a variable displacement pump. When the pump is configured for very low displacement, it creates a small volume of oil flow, causing the hydraulic motor(s) to show additional slowly and gradually. Here's the solutions to your CVT inquiries, such as what's a CVT, https://gearboxcvt65308.iyublog.com/31617055/the-ultimate-guide-to-gearbox-cvt