Designing vehicle exteriors requires repeated refinement of key proportions and viewpoints, a process traditionally reliant on manual sketching, which is often time-consuming and inefficient in early concept stages. To accelerate the design process, we are exploring the potential of utilizing AI for ideation in these early stages. However, it remains a challenging task to control proportions and maintain a fixed perspective when generating images using AI. To address these limitations, we present RatioMorph, a controllable image generation system that enables manipulation of vehicle proportions and viewpoints when generating images by AI. RatioMorph comprises two core modules. Car2BoxNet is a depth estimation model that transforms real photographs into structured box-style depth maps that capture the geometric layout of the vehicle. Box2CarNet is a diffusion-based image generator fine-tuned to produce vehicle designs that adhere to the provided geometric conditions. Both Car2BoxNet and Box2CarNet are trained on a synthetic dataset curated through automated filtering based on geometric alignment and visual quality. Evaluated within a production-adjacent automotive design workflow, RatioMorph significantly reduced early-stage design iteration time and enabled exploratory workflows that were difficult with previous AI workflows. This work introduces a domain-specific, controllable diffusion-based generation system tailored for automotive design, enabling manipulation of vehicle viewpoint and proportion. It demonstrates strong potential to accelerate early-stage workflows and outlines a path toward industrial deployment, with phased integration into production environments currently underway.

There are many types of wheelchairs. Users are able to choose suitable wheelchair for their purposes. Power-assisted wheelchairs are one type of wheelchairs, which use both propelling torque from human and output torque from motors for their driving force. To improve assist performance, many assist control systems were proposed. One of conventional assist control, proposed by Seki et al., is designed for motion of traveling in straight line. However, it is difficult for wheelchair users to rotate using conventional assist control. In this paper, a novel two-dimensional assist control for power-assisted wheelchairs is proposed. The proposed assist control system is designed for both straight and rotational motion of wheelchair, therefore, power assist performance in rotating motion is improved compared to conventional system.