$attributeSetId = 20;//your_attributeSetId
    $attributeSet = $this->objectManager->create('MagentoEavApiAttributeSetRepositoryInterface');
    $attributeSetRepository = $attributeSet->get($attributeSetId);
    $attribute_set_name = $attributeSetRepository->getAttributeSetName();
    $attributeGroupCollection = $this->objectManager->get ( 'MagentoEavModelEntityAttributeGroup' )->getCollection ();
    $attributeGroupCollection->addFieldToFilter ( 'attribute_group_name', $attribute_set_name );
    $attributeGroupCollection->addFieldToFilter ( 'attribute_set_id', $attributeSetId );
    $attributeGroupId = '';
    foreach ( $attributeGroupCollection as $attributeGroup ) {
        $attributeGroupId = $attributeGroup->getId ();
        break;
    }
    $attributeCollection = $this->objectManager->get ( 'MagentoEavModelEntityAttribute' )->getCollection ();
    $attributeCollection->setAttributeSetFilter ( $attributeSetId );
    $attributeCollection->setAttributeGroupFilter ( $attributeGroupId );

    echo "<pre>";
    print_r($attributeCollection->getData());

$attributeSetId = 20;//your_attributeSetId
$productAttributesManagement = $this->objectManager->create('MagentoCatalogApiProductAttributeManagementInterface');
$productAttributes = $productAttributesManagement->getAttributes($attributeSetId);